Estimation of diversity and combining abilities in Helianthus annuus L. under water stress and normal conditions.

Sunflower cannot produce high yields under water-limiting conditions. The aim of the present study was to prevent the impediments on yield and to develop varieties with high-yield potential under water scarce conditions. For achieving this objective, it is necessary to detect parents with desirable traits that mainly depend on the action of genes controlling the trait under improvement, combining ability, and genetic makeup of the parents. Heterosis can also be used to pool the desirable genes from genetically divergent varieties and these divergent parents could be detected by molecular studies. Ten tolerant and five susceptible tester lines were selected, crossed, and tested for genetic diversity using simple sequence repeat primers. We identified two parents (A-10.8 and G-60) that showed maximum (46.7%) genetic dissimilarity. On an average 3.1 alleles per locus were detected for twenty pair of primers. Evaluation of mean values revealed that under stress conditions the mean performances of the genotypes were reduced for all traits under study. Parent A-10.8 was consistent as a good general combiner for achene yield per plant under both non-stress and stress conditions. Line A-10.8 in the hybrid A-10.8 x G-60 proved to be a good combiner as it showed negative specific combining ability (SCA) effects for plant height and internodal length and positive SCA effects for head weight, achene yield per plant, and membrane stability index. Valuable information on gene action, combining ability, and heterosis was generated, which could be used in further breeding programs.

An insight in the genetic control and interrelationship of some quality traits in Brassica napus.

A study on three leading lines (KN-256, KN-257, and KN-258) of Brassica napus and an approved variety, Punjab-Sarson, was conducted to gain insight into the genetic control of some quality traits using generation mean analysis. Our results showed that additive gene action predominated in the inheritance of oil content and erucic acid in cross KN-256 x KN-257 and in that of glucosinolates in KN-258 x Punjab-Sarson, indicating that these traits may be improved through selection in early segregating generations. Negative dominance can be exploited through heterosis breeding for the development of lines with low glucosinolates in cross KN-256 x KN-257. Protein content and oleic acid in cross KN-256 x KN-257, and oil content, protein content, and erucic acid in cross KN-258 x Punjab-Sarson depicted non-additive gene action and require further improvement in the later segregating generations. Most of the traits displayed high heritability estimates; glucosinolate content in both the crosses and erucic acid in cross KN- 258 x Punjab-Sarson also displayed high genetic advance, reflecting improvement of the trait in the early segregating generations. All the quality traits were positively correlated with oil content and with one another at both (genotypic and phenotypic) levels in KN-256 x KN-257. Negative correlation was observed between glucosinolate and erucic acid, oleic acid and erucic acid, and linolenic acid and oil content in cross KN-258 x Punjab-Sarson. Thus, gene action changed with the material, and cross KN-258 x Punjab-Sarson carried favorable combinations compared to KN-256 x KN-257.

Estimation of genetic diversity using SSR markers in sunflower.

Microsatellites or simple sequence repeats (SSRs) were used for the estimation of genetic diversity among a group of 40 sunflower lines developed at the research area of Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad. Total numbers of alleles amplified by 22 polymorphic primers were 135 with an average of 6.13 alleles per locus, suggesting that SSR is a powerful technique for assessment of genetic diversity at molecular level. The expected heterozygosity (PIC) ranged from 0.17 to 0.89. The highest PIC value was observed at the locus C1779. The genetic distances ranged from 9 to 37%. The highest genetic distance was observed between the lines L50 and V3. Genetic distances were low showing lesser amount of genetic diversity among the sunflower lines.

Development of a species-specific sequence-characterized amplified region marker for roses.

DNA fingerprints of four rose species, Rosa centifolia, R. Gruss-an-Teplitz, R. bourboniana, and R. damascena, were developed using RAPD-PCR. We identified a unique polymorphic band in R. centifolia. This 762-bp fragment was produced by the random primer GLI-2. The fragment was eluted and directly cloned in a TA cloning vector, pTZ57R/T. Digestion of the plasmid with EcoRI confirmed the cloning of GLI-2(762) in pTZ57R/T. A second enzyme, PstI, used in combination with EcoRI, gave complete digestion of the plasmid, and the 762-bp fragment was confirmed on the gel. Subsequently, the polymorphic amplicon was sequenced with an AB1 373 DNA sequencer system using the PRISM(TM) Ready Reaction DyeDeoxy(TM) Terminator Cycle Sequencing kit. After sequencing, specific primers (23 bp long) were designed based on the sequence of the flanking regions of the original RAPD fragment. These primers will effectively allow fingerprinting for the identification of R. centifolia species. In essence, we developed an SCAR marker to authenticate the identity of R. centifolia species and to distinguish it from its substitutes. Such techniques are required not only to complement conventional parameters in creating the passport data of commercial and medicinal products of rose, but also for routine quality control in commercial and government rosaries and rose nurseries.

Estimation of genetic distance based on RAPDs between 11 cotton accessions varying in heat tolerance.

The genetic distance of 11 cotton genotypes varying in heat tolerance was studied using RAPD markers. Fifty-three random decamer primers were used for the estimation of genetic distance. Among the 53 RAPD primers, which were custom synthesized by GeneLink Inc., UK, 32 were polymorphic and 21 were monomorphic. The 32 polymorphic primers produced 273 fragments, with a mean of 8.3 fragments per primer. The number of polymorphic bands produced in the 11 cotton accessions ranged from 1 to 31. Primer GLC-20 produced 31 polymorphic bands, while two primers, GLB-5 and GLC-12, produced one polymorphic band each. A range of 88.89 to 42.48% genetic similarity was observed among the 11 cotton accessions. The highest genetic similarity was observed between FH-945 and BH-160 (88.89%), whereas the lowest value was found between NIAB-801/2 and FH-945 (42.48%). Unique amplification profiles were produced by most of the cultivars; the differences were sufficient to distinguish them from other genotypes. This confirms the efficacy of RAPD markers for the identification of plant genotypes. An accumulative analysis of amplified products generated by RAPDs was sufficient to assess the genetic diversity among the genotypes. This information should be helpful for formulating breeding and genome mapping programs.

Identification of sunflower (Helianthus annuus, Asteraceae) hybrids using simple-sequence repeat markers.

Hybrid identification of 16 sunflower hybrids was confirmed using simple-sequence repeat methodology. Of 20 specific simple-sequence repeat primers, 18 authenticated the purity of these hybrids; the remaining two specific primer pairs gave ambiguous DNA fragments. The results indicate that simple-sequence repeat analysis for the identification of hybrids derived from the crossing of different inbred sunflower lines can improve the accuracy of selection, save time and reduce cost.

Genetic diversity of chickpea (Cicer arietinum L.) germplasm in Pakistan as revealed by RAPD analysis.

Genetic diversity analysis of chickpea germplasm can provide practical information for the selection of parental material and thus assist in planning breeding strategies. Chickpea seed is a good source of carbohydrates and proteins, constituting 80% of the total dry seed weight. Released cultivars and advanced lines of 30 chickpea genotypes were subjected to RAPD analysis for assessment of genetic diversity. We used 16 RAPD primers. Amplification of genomic DNA of the 30 genotypes yielded 62 fragments that could be scored. The number of amplification products produced per primer varied from two to four, with a mean of three bands. The total number of bands amplified by 16 anchored primers varied from 16 to 34. The primer GLK-15 produced the largest number (N = 4) of fragments, whereas primers GLK-19 and GLD-19 produced the smallest number (N = 1) of fragments. The single band produced by the GTGTGCCCCA primer in the PB-2000 and 07005 genotypes may be attributed to temperature tolerance phenotypes.

Biodiversity in the sorghum (Sorghum bicolor L. Moench) germplasm of Pakistan.

Sorghum ranks fifth in worldwide economic importance among cereal crops and is one of the most important summer annual grasses of Pakistan. As it is a very diverse crop, sorghum genetic fingerprinting requires an efficient marker system. We estimated genetic divergence among 29 sorghum (Sorghum bicolor) genotypes, including approved varieties and local and exotic lines collected from different ecological regions of Pakistan, using random amplified polymorphic DNA (RAPD) markers. A total of 125 RAPD loci, with an average of 66 loci per genotype, were used to calculate genetic divergence among these genotypes, of which 119 were polymorphic, showing 95% overall polymorphism. Genetic similarity ranged from 0.36 to 0.92, indicating a relatively broad genetic base. RAPD analysis revealed maximum similarity between the Indian III and K-A-113 sorghum genotypes (both exotic lines), while the F-601 and F-606 were observed to be the most diverse genotypes. Mean band frequency revealed by these RAPD primers ranged from 0.17 to 0.56, with an average of 0.36. The data presented here support the findings that RAPDs can be effectively used for studying genetic diversity in sorghum.

Estimation of genetic diversity among sunflower genotypes through random amplified polymorphic DNA analysis.

The genetic diversity among eight sunflower lines was determined through the estimation of the random amplified polymorphic DNA method. One hundred and fifty-six DNA fragments were generated by 20 random primers, for an average of about 7.8 bands per primer. Of these amplified DNA fragments, 104 were polymorphic among the eight sunflower lines. Nei and Li's similarity matrix gave values from 51.59 to 77.78%, which indicated a broad genetic base. The maximum similarity, 77.78%, was observed between R-SIN-82 and RN-46. The lowest similarity, 51.59%, was observed between the exotic lines CM-612 and HA-27. After knowing the knowledge of genetic diversity based on these random amplified polymorphic DNA markers, highly diverse lines can be used for further breeding programs to develop an ideal local hybrid of sunflower.