Genetic Diversity, Population Structure and Marker-Trait Association for 100-Seed Weight in International Safflower Panel Using SilicoDArT Marker Information.

Safflower is an important oilseed crop mainly grown in the arid and semi-arid regions of the world. The aim of this study was to explore phenotypic and genetic diversity, population structure, and marker-trait association for 100-seed weight in 94 safflower accessions originating from 26 countries using silicoDArT markers. Analysis of variance revealed statistically significant genotypic effects (p < 0.01), while Turkey samples resulted in higher 100-seed weight compared to Pakistan samples. A Constellation plot divided the studied germplasm into two populations on the basis of their 100-seed weight. Various mean genetic diversity parameters including observed number of alleles (1.99), effective number of alleles (1.54), Shannon's information index (0.48), expected heterozygosity (0.32), and unbiased expected heterozygosity (0.32) for the entire population exhibited sufficient genetic diversity using 12232 silicoDArT markers. Analysis of molecular variance (AMOVA) revealed that most of the variations (91%) in world safflower panel are due to differences within country groups. A model-based structure grouped the 94 safflower accessions into populations A, B, C and an admixture population upon membership coefficient. Neighbor joining analysis grouped the safflower accessions into two populations (A and B). Principal coordinate analysis (PCoA) also clustered the safflower accessions on the basis of geographical origin. Three accessions; Egypt-5, Egypt-2, and India-2 revealed the highest genetic distance and hence might be recommended as candidate parental lines for safflower breeding programs. The mixed linear model i.e., the Q + K model, demonstrated that two DArTseq markers (DArT-45483051 and DArT-15672391) had significant association (p < 0.01) for 100-seed weight. We envisage that identified DArTseq markers associated with 100-seed weight will be helpful to develop high-yielding cultivars of safflower through marker-assisted breeding in the near future.

Environment effects for earliness and grain yield traits in F1 diallel populations of maize (Zea mays L.).

BACKGROUND: Five maize inbred lines, 20 F1 diallel hybrids and two check genotypes were evaluated through genotype × environment interaction (GEI) and GGE biplot for earliness and yield traits at four locations. RESULTS: Genotype, environment and GEI showed highly significant differences for all the traits. In total sum of squares, environment and genotype played a primary role, followed by GEI. Larger effects of environment and genotype to total variation influence the earliness and yield traits. However, according to the GGE biplot, the first two principal components (PC1 and PC2) explained 95% of the variation caused by GEI. GGE biplot confirmed the differential response of genotypes across environments. F1 hybrid SWAJK-1 × FRHW-3 had better stability, with a good yield, and was considered an ideal genotype. F1 hybrid FRHW-2 × FRHW-1 showed more earliness at CCRI and Haripur, followed by PSEV3 × FRHW-2 and its reciprocal at Swat and Mansehra, respectively. F1 hybrids FRHW-1 × SWAJK-1, PSEV3 × SWAJK-1 and SWAJK-1 × FRHW-3 at Mansehra and Swat produced maximum grain yield, followed by SWAJK-1 × FRHW-1 and PSEV3 × FRHW-1 at Haripur and CCRI, respectively. CONCLUSION: Overall, maize genotypes showed early maturity in plain areas (CCRI and Haripur) but higher yield in hilly areas (Mansehra and Swat). © 2017 Society of Chemical Industry.

Recurrent selection for maydis leaf blight resistance and grain yield improvement in maize.

Leaf blight of maize (Zea mays L.), caused by Bipolaris maydis (Nisik. and Miyake), is one of the major factors limiting maize production in the plain areas of Pakistan, particularly in the North West Frontier Province (NWFP). The objectives of this study were to estimate selection differential, expected and observed response to selection and heritability for maydis leaf blight resistance and grain yield and to determine progress from selection in a maize population. Two cycles of S, recurrent selection were conducted in broad based maize population, Sarhad White (SW). One hundred S, lines were compared with their respective original population (C0) as a check. The experimental material was evaluated under artificial epiphytotics during 2003 and 2004, at NWFP Agricultural University, Peshawar. Selection differentials, expected responses and heritability estimates were determined from the replicated S1 lines performance of the first cycle. The observed progress was estimated from the replicated S1 lines of the second cycle that were generated after recombination of selected S1 lines of the first cycle. Highly significant variations between the cycles were observed for MLB and grain yield. Moderate and high heritability estimates, desirable selection differentials and close correspondence of expected and observed response were manifested for MLB and grain yield. The positive percent deviation of inoculated from uninoculated trials in both cycles (C1 = 71% and C2 = 41%) for leaf blight indicated successful development of blight disease after artificial inoculation, while the negative percent deviation of inoculated form uninoculated trials (C1 = -21 and C2 = -6%) for grain yield indicated the impact of blight disease on grain yield. Blight disease was significantly reduced from 2.9 to 2.3, whereas, grain yield was significantly increased from 2041 kg ha(-1) cycle(-1) to 2527 kg ha(-1) cycle(-1) or 19% cycle(-1). This yield improvement in SW was probably the result of concomitant reduction in the blight disease severity by -26%. These findings suggested that S1 recurrent selection was quite effective in improving disease resistance and grain yield. Nevertheless, some additional cycles of selection may be required to further improving grain yield and resistance level to maydis leaf blight in SW maize population.