Genetic variability of cocoa from the amazon basin: implications for genetic conservation

The cocoa and chocolate production chain involves US$60 billion annually and three million farmers around the world, in an area exceeding nine million hectares. The use of wild germplasm will enable to generate new disease- and pest-resistant cultivars and ability to adapt to changing environments. Here we evaluated 145 cocoa accessions, originated from nine Amazonian basins, based on eight fruit traits. Univariate anova showed significant differences (p<0.05) for all traits. For seven traits, the variance component within basins was higher (81.5%, on average). Therefore, it is recommended that the collection of wild accessions prioritize a larger number of plants from a few populations of the most divergent basins. The multivariate analyses revealed a greater divergence between the Ji-Paraná-RO and Solimões/Amazonas-PA basins (27.69) and a greater similarity between Alien clones-PER and Solimões/Amazonas-AM (0.66) in relation to their populations. They also revealed that the accessions differentiation occurred according to the river basin system. These results allowed elucidate the genetic structure and distribution of cacao populations. In addition, strengthen the importance of collecting and conserving germplasm to preserve genetic resources.

Evaluation of adaptability and stability for iron, zinc and protein content in cowpea genotypes using GGE biplot approach.

Cowpea is a widely cultivated crop in the world. Biofortification strategies aim to reduce mineral and protein deficiencies, especially among the poorest people. The aim of this study was to estimate adaptability and stability of cowpea genotypes for iron, zinc and protein contents, through GGE biplot analysis. Twenty cowpea genotypes were evaluated in the municipalities of Piauí Monsenhor Hipólito, Pio IX and São Miguel do Tapuio, under rainfed conditions. The experimental design was a randomized block design with four replications. The traits evaluated were grain yield, iron, zinc and protein contents in dry grains. Iron (Fe) and zinc (Zn) were determined by flame atomic absorption spectrophotometer, and protein contents by Kjeldahl methods. Adaptability and stability were evaluated by GGE biplot analyses. The means of the experiments were 1,209.1 kg ha-1, 51.1 mg kg-1, 46.8 mg kg-1 and 24.3% for grain yield, Fe, Zn and protein contents, respectively. The joint analysis of variance showed significant difference (p < 0.05) for the effect of interaction genotypes by environments for Fe, Zn and protein contents. The lines G6 and G8 were the most promising for grain yield, mineral and protein content through adaptability and stability by GGE biplot approach.

Exogenous brassinosteroids increase lead stress tolerance in seed germination and seedling growth of Brassica juncea L.

Lead (Pb) is a highly toxic heavy metal to plants, animals, and human beings. The use of growth regulators has reversed the effects of heavy metal stress on germination and early plant development. The aim of this study was to evaluate the effect of brassinosteroids on seed germination and seedling growth of Brassica juncea (L.) Czern. & Coss. under Pb stress conditions. Two forms of application of 24-epibrassinolide (EBL) were evaluated, application on seeds in pre-soaking and on germination paper, using EBL concentrations of 0, 10-10, 10-8, and 10-6 M. Germination and seedling growth parameters were evaluated during the germination test. The activity of the enzymes superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase were determined, as well as the lead content in the seeds and seedlings. The EBL applied at the 10-8 M concentration was the most effective in overcoming Pb stress in both forms of application. The antioxidant enzyme defense system was compromised by Pb exposure. However, 10-8 M EBL increased the activity of antioxidant enzymes such as catalase and peroxidase to overcome the toxic effects caused by Pb. In addition, EBL at the concentration of 10-8 M increased Pb content in seedlings without affecting seedling growth.

Qualidade e compostos fenólicos em sementes de mamão alterados pela colheita e maturação dos frutos / Quality and phenolic compounds in papaya seeds changed by harvest and maturity of fruits

A presença de compostos fenólicos nas estruturas das sementes de mamão pode interferir no processo de germinação, de forma que o objetivo no estudo foi avaliar o efeito da época de colheita e da maturação dos frutos sobre a ocorrência de compostos fenólicos e qualidade de sementes de mamão. Os frutos foram colhidos em abril e outubro de 2010 e as sementes extraídas nos estádios 1, 3, 5 e final da maturação, correspondendo a cerca de 15, 50, 75 e 100% da casca amarela, respectivamente. Em cada estádio, sementes com e sem sarcotesta foram avaliadas quanto à porcentagem de germinação, primeira contagem, envelhecimento acelerado, sementes dormentes e conteúdo de fenóis nas sementes pelo método de Folin-Ciocalteau em delineamento inteiramente ao acaso. As sementes com maior porcentagem de germinação e nível de vigor foram as dos frutos no estádio 5 e final da maturação; a sarcotesta contém maior concentração de fenóis em relação às demais estruturas.

The presence of phenolic compounds in the papaya seed structures can interfere with the germination process, so the objective in the study was to evaluate the effect of the harvest season and maturation stage of the fruit changing the inhibitory compounds presence and physiological quality in papaya seeds. Fruits of papaya were collected in April and October, 2010, and seeds extracted of the stage 1, 3, 5 and final of maturation, corresponding to about 15, 50, 75 and 100% of yellow peel respectively. Seeds with and without sarcotesta were evaluated by test of germination, first counting, accelerated aging, percentage of dormant seeds, and content of phenols in seed by method of Folin-Ciocalteau in completely randomized design The Seeds with higher germination and vigor level were the fruits at stage 5 and final of maturation. The sarcotesta contains a higher concentration of phenols in relation to other structures.

Armazenamento de sementes de pinhão manso em diferentes embalagens e ambientes / Storage of phisic nut seeds in different environments and packagings

O presente trabalho teve como objetivo avaliar a qualidade fisiológica de sementes de pinhão manso armazenadas em diferentes embalagens e ambientes. O experimento foi conduzido na Universidade Federal de Viçosa, em Viçosa-MG. As sementes, com teor de água de 8,3%, foram acondicionadas em embalagem de pano e de plástico e armazenadas por 450 dias em condições de laboratório (sem controle de temperatura e U.R.); sala refrigerada (18 a 20 ºC e 55 a 60% de U.R.); câmara fria (10 a 12 ºC e 55 a 60% de U.R.) e câmara fria (5 a 7 ºC e 60 a 65% de U.R.). No início do armazenamento e a cada 90 dias, foram determinados o teor de água, a germinação e o vigor das sementes. Redução na qualidade fisiológica das sementes de pinhão manso ocorreu durante o armazenamento, independentemente das condições de ambiente e embalagem. As sementes podem ser armazenadas por 270 dias em ambiente não controlado, em Viçosa- MG. Para armazenamento por tempo superior a 270 dias, é recomendada a utilização de ambiente refrigerado, com temperatura 18-20 °C, independentemente da embalagem utilizada.

The study aimed to evaluate the physiological quality of seeds of physic nut stored at different environment and packaging. The experiment was conducted at the Federal University of Viçosa-MG. The seeds, with water content of 8,3%, were packed in cloth and plastic and stored for 450 days under laboratory conditions (no temperature an R.U. control); air-conditioned room (18 to 20 ºC and 55 to 60% R.U.), refrigerated chamber (10 to 12 °C and 55 to 60% R.U.) and refrigerated chamber (5-7 °C and 60 to 65% R.U.). At the beginning of storage and every 90 days, we determined the water content, germination and vigor of seeds. Reduction in the physiological quality of seeds of physic nut occurred during storage, regardless of the environment and packaging. The seeds can be stored for 270 days at room without controlled temperature and relative humidity, in Viçosa-MG, both in plastic packaging such as cloth. From 270 days, it is recommended to use refrigerated environment, with temperatures 18-20 °C for seed storage, regardless of packaging used.

Susceptibility and physiological responses of Jatropha curcas accessions to broad mite infestation.

The broad mite Polyphagotarsonemus latus is a key pest of physic nut (Jatropha curcas L.). The purpose of this study was to identify physic nut accessions that are less susceptible to P. latus, in support of the breeding program of J. curcas. We first evaluated population growth rate and injury symptoms of P. latus on different J. curcas accessions and then carried out physiological analyses on P. latus-infested and uninfested accessions. From the germplasm bank of the Federal University of Viçosa, 15 physic nut accessions with high seed oil content, with different genetic background, were tested. The following traits were evaluated: instantaneous population growth rate of P. latus (r i ), injury symptoms, relative leaf water content, specific leaf area, gas exchange, photosynthetic pigments, nitrogen and biomass of the aerial part. Significant differences were observed for P. latus population growth rate and injury symptoms among accessions. A positive correlation between P. latus growth rate and injury was found. The UFVJC72 accession stood out as the more resistant, considering P. latus growth rate and injury symptoms, compared with most accessions. Physiological responses did not vary among accessions, but did between infested and uninfested plants. In P. latus-infested plants, net photosynthesis was on average 50.5 % lower than in uninfested plants, whereas stomatal conductance and transpiration decreased by 46.2 and 51.6 %, respectively.

SP-index: the measure of the scientific production of researchers.

Ability to assess how solidly one is participating in their research arena is a metric that is of interest to many persons in academia. Such assessment is not easily defined, and differences exist in terms of which metric is the most accurate. In reality, no single production metric exists that is easy to determine and acceptable by the entire scientific community. Here we propose the SP-index to quantify the scientific production of researchers, representing the product of the annual citation number by the accumulated impact factors of the journals whereby the papers appeared, divided by the annual number of published papers. This article discusses such a productivity measure and lends support for the development of unified citation metrics for use by all participating in science research or teaching.

Componentes primários e secundários do rendimento de óleo de pinhão-manso / Primary and secondary yield components of the oil in physic nut (Jatropha curcas L.)

A definição dos critérios para seleção de materiais é especialmente importante para o cultivo do pinhão-manso (Jatropha curcas L.), pois subsidia a caracterização dos ideótipos mais adequados para o plantio e o progresso genético com a prática da seleção. O objetivo deste trabalho foi estimar, por meio de análise de trilha com diagrama em cadeia, os efeitos diretos e indiretos de sete características vegetativas e quatro características de qualidade da matéria-prima sobre o rendimento de óleo de pinhão-manso com 38 meses de cultivo. A produtividade de grãos e o teor de óleo apresentaram efeito direto e positivo sobre o rendimento de óleo, e o volume de copa mostrou-se como um dos principais componentes de efeito indireto e positivo sobre a variável principal. Na população de melhoramento avaliada, as estimativas dos efeitos diretos e indiretos indicaram que a seleção de plantas de maior rendimento de óleo deve considerar genótipos de maior produtividade de grãos e maior volume de copa, mantendo-se a variabilidade para as outras características avaliadas.

The definition of the most suitable plant selection criteria is especially important for Jatropha curcas L. as subsidies the genetic progress estimates and the ideotype characterization, described in terms of the traits that are thought to enhance genetic yield potential. The objective of this study was to estimate the direct and indirect effects of seven vegetative traits and four seed quality traits on J. curcas oil yield. The traits grain yield and the weight of the nuts showed direct and positive effect on the oil yield. The tree volume showed the major indirect and positive effect on the main variable through grain yield. The development of J. curcas with higher oil yield in the evaluated population has to consider the selection of plants with higher yield and tree volume, maintaining the variability of the grain quality traits.

Testes de vigor para avaliação do potencial fisiológico de sementes de mamona (Ricinus communis L. ) / Vigor test for the evaluation of the physiology potencial of (Ricinus communis L. ) seeos

A qualidade de sementes de mamona tem sido avaliada rotineiramente pelo teste de germinação, cujos resultados, muitas vezes, não são confirmados em campo. Nesse contexto, os testes de vigor são essenciais, pois retratam o comportamento das sementes sob maior amplitude de ambiente. Neste trabalho, objetivou-se avaliar a eficiência de métodos para determinar o potencial fisiológico de sementes de mamona. Para tanto, foram utilizados sete lotes de sementes de mamona, cultivar AL-Guarany, apresentando teor de água de aproximadamente 7 por cento , que foram submetidos aos seguintes testes: germinação, primeira contagem de germinação, frio (a 10ºC/7 dias e a 25ºC/5 dias), porcentagem e velocidade de emergência de plântulas, envelhecimento acelerado a 41ºC e 45ºC e 100 por cento UR, por 48, 72 e 96 horas e condutividade elétrica (25 sementes embebidas em 75 e 100mL de água destilada, a 25ºC, por 2, 4, 6, 8, 24, 48 e 72 horas). Os testes de frio e de envelhecimento acelerado (41ºC/72 horas e 100 por cento UR) foram eficientes para avaliação do potencial fisiológico de sementes de mamona, permitindo classificação de lotes quanto ao vigor semelhante à emergência de plântulas em solo. O teste de condutividade elétrica não se mostrou adequado para avaliação do potencial fisiológico das sementes de mamona.

This work had the objective to determine the efficiency of different tests for the evaluation of physiological potential of castor bean seeds. Seven seed lots of AL-Guarany cultivar were submitted to the following tests: seed moisture content, standard germination, first count, cold test (10ºC/7 days followed by germination at 25ºC/5 days), seedling emergence, speed emergence index, accelerated aging (at 41ºC and 45ºC and 100 percent RH, for 48, 72, and 96h) and electrical conductivity (25 seeds soaked into 75 and 100mL of distilled water, at 25ºC, for 2, 4, 6, 8, 24, 48, and 72 h). The trial was conducted in randomized completely design, with four replications. The means of treatments were compared by Tukey test at 5 percent probability. Results showed that cold test and accelerated aging (41ºC/72 hours) were efficient to evaluate the physiological potential of castor bean seeds, allowing the classification of lots regarding vigor to be similar to the seedling emergence test. Electrical conductivity test was not adequate for the evaluation of physiological potential of these seeds.

Cacao yield in different planting densities

The effect of six planting densities on cacao yield of a commercial hybrid mixture as well as the interaction of planting densities with the years were investigated. Crop data collected over a 14-year period (1977-1990) showed that it was possible to optimise the regional cacao yields by implementing high planting densities (2500 and 1736 trees ha-1). This was however only true for the first half of the crop period. In the second half, low planting density (1059 trees ha-1) attained the best yields. This change in the ranking of planting densities over the years confirmed the presence of density-year interaction. Alternatives to achieve high productivity in high planting density systems were presented and discussed.

O efeito de seis densidades de plantio sobre a produção de um híbrido comercial de cacau, bem como a interação das densidades com os anos, foi investigado. Dados coletados do cultivo por 14 anos (1977-1990) mostraram que é possível otimizar a produção de cacau da região implementando uma alta densidade populacional (2500 e 1736 plantas ha-1). Todavia, isto se verificou apenas para a primeira metade do período de cultivo. Na segunda metade, a baixa densidade (1059 plantas ha-1) foi superior em produção. Esta mudança na densidade com o passar dos anos foi confirmada pela presença da interação densidades por anos. Alternativas para alcançar elevadas produtividades nos sistemas com altas densidades foram apresentadas e discutidas.

Prediction of genotypic values and estimation of genetic parameters in common bean

Eighteen common bean (Phaseolus vulgaris L.) genotypes were evaluated in 25 environments of the state of São Paulo in 2001 and 2002. The estimation of genetic parameters by the Restricted Maximum Likelihood (REML) and the prediction of genotypic values via Best Linear Unbiased Prediction (BLUP) were obtained by software Selegen-REML/BLUP. The estimate of the broad-sense heritability was low for the grain yield (0.03), since it took individual plots into consideration and was free of the effects of interaction with years, cultivation periods and site. Nevertheless, the heritability at the level of line means across the various environments was high (0.75), allowing a high accuracy (0.87) in the selection of lines for planting in the environment mean. Among the 18 genotypes, the predicted genotypic values of nine were higher than the general mean. The genetic gain predicted with the selection of the best line, in this case line Gen 96A31 of the IAC, was 16.25 percent.

Dezoito genótipos de feijoeiro (Phaseolus vulgaris L.) foram avaliados em 25 ambientes do estado de São Paulo durante os anos de 2001 e 2002. As estimativas de parâmetros genéticos por REML e a predição de valores genotípicos via BLUP foram obtidas por meio do aplicativo computacional Selegen REML/BLUP, seguindo o modelo misto para linhagens. A estimativa da herdabilidade no sentido amplo para produção de grãos foi baixa (0,03), por ser em nível de parcelas individuais e livre dos efeitos da interação com anos, épocas e locais. No entanto, a herdabilidade ao nível de médias de linhagens ao longo dos vários ambientes foi alta (0,75), permitindo alta acurácia (0,87) na seleção de linhagens para plantio no ambiente médio. Dentre os 18 genótipos, nove apresentaram valores genotípicos preditos superiores à média geral. O ganho genético predito com a seleção da melhor linhagem, no caso, a linhagem Gen 96A31 do IAC, foi de 16,25 por cento.

Selection among and within and combined selection in oil palm families derived from Dura x Dura / Seleção entre e dentro e seleção combinada em famílias de dendê oriundas do cruzamento Dura x Dura

Oil palm, in view of the worldwide consumed oil, is a perennial crop of great importance. Nevertheless, the genetic improvement is still incipient. In this study we applied the selection among and within families and the combined selection, based on the phenotypic values and phenotypic performance (Pi statistic), to verify which strategy obtained the highest genetic gains. Five full-sib families were evaluated in randomized blocks, with five replicates and 12 plants per plot, over five years of successive harvests. The total number of bunches and the total fruit yield per year plant-1 were evaluated. Values of 1.00 and 0.25 for the ratio between the environmental variance among plots and the environmental variance among plants within the plot for both traits, respectively, were adequate for the estimation of the genetic parameters. The existence of genetic variability in the population Dura was verified for both evaluated traits. The combined selection, based either on the phenotypic values or on the underlying Pi statistic, resulted in the highest genetic gains. Despite the satisfactory gains since it translates the true yield potential of the evaluated genotypes and their performance stability.

O dendê é uma cultura perene de grande importância devido à produção de óleo que é consumido mundialmente. Contudo, o melhoramento genético ainda é incipiente. Neste trabalho foram utilizadas a seleção entre e dentro de famílias e a seleção combinada, a partir dos valores fenotípicos e da performance fenotípica (estatística Pi), visando verificar com qual das estratégias foi obtido maior ganho genético. Avaliaram-se cinco famílias de irmãos-completos em blocos casualizados, com cinco repetições e 12 plantas por parcela, durante cinco anos de colheitas sucessivas. O número total de cachos e a produção total de frutos por ano planta-1 foram avaliados. Valores de 1,00 e 0,25 para a razão entre a variância ambiental entre parcelas e a variância ambiental entre plantas dentro da parcela, respectivamente para ambas as características, foram adequados para a estimação dos parâmetros genéticos. Verificou-se a existência de variabilidade genética na população Dura para as duas características avaliadas. A seleção combinada, tanto baseada nos valores fenotípicos ou fundamentada na estatística Pi, proporcionou maiores ganhos genéticos. Embora a seleção entre e dentro de famílias tenha proporcionado ganhos satisfatórios, recomenda-se o processo de seleção baseado na estatística Pi, pois a mesma irá traduzir o verdadeiro potencial produtivo dos genótipos avaliados e a sua estabilidade de comportamento.

Genetic divergence between populations of the stingless bee uruçu amarela (Melipona rufiventris group, Hymenoptera, Meliponini): is there a new Melipona species in the Brazilian state of Minas Gerais?

Allozyme, microsatellite and random amplified polymorphic DNA (RAPD) molecular markers were used to investigate the within and between population genetic variability and between population genetic differentiation of the Brazilian stingless bee uruçu amarela (nominally Melipona rufiventris Lepeletier, 1836) present in savanna and Atlantic forest habitats of the Brazilian state of Minas Gerais (MG). We found low levels of within population variability, although there were a large number of private alleles that specifically characterized these populations. The F ST values indicated a high level of genetic diversity between populations. Analysis of molecular variance (AMOVA) showed a high degree of population differentiation between the savanna and Atlantic forest habitats, confirmed by population pairwise F ST data. Principal coordinates analysis and unweighted pair-group method using an arithmetic average (UPGMA) dendrograms also confirmed that in Minas Gerais the savanna populations (M. rufiventris) were genetically distinct from those present in the Atlantic forest (M. mondury). In addition, populations from locations near the towns of Dom Bosco and Brasilândia de Minas were genetically different from those collected in other localities in the savanna. Our data indicate that populations of uruçu amarela found in the savanna and Atlantic forest habitats of Minas Gerais state should be treated separately for conservation purposes and that special attention should be given to the populations found in the region of Dom Bosco and Brasilândia de Minas until their taxonomic status is clarified.

Identification of common bean ( Phaseolus vulgaris ) duplicates using agromorphological and molecular data

We used agromorphological and random amplified polymorphic DNA (RAPD) molecular marker data to identify duplicate common bean (Phaseolus vulgaris L. Fabaceae) accessions in the Common Bean Germplasm Bank of the Agronomical Institute - IAC (Banco de Germoplasma de feijoeiro do Instituto Agronômico de Campinas (IAC), SP, Brazil). A total of 116 accessions with the same names and similar agromorphological traits was analyzed. The divergence between the accessions was initially evaluated by means of the agromorphological descriptors using single linkage clustering, from the Euclidean distance. Multivariate analysis identified four duplicate accessions (Carioca Lustroso, Bico de Ouro, Jamapa and Preto), with 17 other same-name accessions being suspected duplicates due to their low divergence levels. Accessions with low genetic distance values (indicating that they were duplicates) were further compared using RAPD markers which confirmed the results of the multivariate analyses in relation to the four duplicate accessions, although only two of the other 17 suspect accessions were confirmed to be duplicates, in this case of accessions IAPAR 57 and Sacavem. These results show that the combined use of agromorphological and molecular information allowed a better characterization of the acessions in the common bean Germplasm Bank.

Isoenzyme variation in Melipona rufiventris (Hymenoptera: Apidae, Meliponina) in Minas Gerais State, Brazil.

The stingless bee Melipona rufiventris is an important pollinator in several Brazilian ecosystems. Originally widely distributed in Minas Gerais (MG) state, this species is becoming very rare. Therefore this species was included in the endangered species list of MG. We used isoenzyme data for a better understanding of the genetic structure of several M. rufiventris colonies. Samples of 35 colonies were collected from 12 localities and evaluated by nine enzymatic systems, which yielded 17 loci. M. rufiventris genetic variation was found to be low, typical of an endangered species. The proportion of polymorphic loci was 5.88% in both ecosystems. Only Est-4 was polymorphic in colonies from the Forest and Mdh-1 in colonies from the Cerrado. The expected heterozygosity ranged from 0.0068 in the Cerrado to 0.0078 in the Forest. Despite this, enzyme electrophoretic analyses provided a good idea of the diversity between samples from Cerrado and Forest which reinforce the existence of two different "forms" of M. rufiventris in MG, one present in the Cerrado and the other in Forest. This information is of great importance for the conservation of M. rufiventris in MG.

A priori choice of hybrid parents in plants.

Plant breeding deals with high-yielding genotypes. However, how best to choose parents of these genotypes remains an unsolved question. Here, we focus on a priori choice based on parental distances by means of agronomic and molecular data. Despite numerous theoretical and empirical studies, a priori choice continues to be a controversial procedure. Both success and failure are commonly reported. We looked at these ambiguous results in order to investigate their possible causes. A total of 139 articles on genetic divergence were sampled to examine aspects such as type and number of markers utilized. We suggest that the mean number of 160, 281 and 25 for RAPD and RFLP markers, and SSR loci, respectively, which we found in these papers, should be increased for accurate analysis. A second sample composed of 54 articles was used to evaluate the divergence-heterosis association. Most of them (28) detected positive divergence-heterosis association, whereas 26 revealed negative or inconclusive results. We examined several causes that influence a priori choice positively and negatively.

Variation and its distribution in wild cacao populations from the Brazilian Amazon

A sample of 64 progenies (320 cacao trees as a whole) from four Brazilian Amazon basins was collected and evaluated on the basis of 15 fruit and seed traits. Nested univariate analyses of variance showed significant variation across progenies and basins. However, most of the variability appeared to be due to among trees and basins differences. The multivariate analysis showed that the differentiation in cacao populations occurred among basins. Since cacao diversity was predominantly found in trees within basins and among basins, one should optimize the collecting process by taking as many trees as possible starting from few progenies and many river basins. These findings seemed to validate gene conservation efforts made to date to preserve the cacao genetic resources and provide insight into the cacao genetic structure aiming cacao collection, management and improvement

Genetic distance and its association with heterosis in cacao

The efficiency of cacao breeding program can be increased by choosing superior crosses to be made between divergent clones. We assessed the genetic distance among five clones with RAPD data (genetic distance - GD) and with yield component data (Mahalanobis distance - MD). The clones were evaluated in a diallel, during five years, for five yield components. A total of 130 RAPD bands were scored. GD and MD were used to determine the correlation between genetic distances among clones and the performance of their hybrids. The correlation between GD and MD was 0.67 (P=0.03). Both distances were related to heterotic performance of hybrids for wet seed weight/plant and wet seed weight/fruit. The average hybrid performance for the same two yield components was correlated with only MD. Hence, genetic distances measured by RAPD and yield components can be used as a guide to the choice of the superior crosses