Genetic diversity and heritability of chlorophyll content and photosynthetic indexes among some Iranian wheat genotypes

Abstract Genetic diversity and heritability of Chlorophyll (Chl) content and some photosynthetic indexes were studied in thirty wheat genotypes through randomized complete block design with three replications at 2009. The maximum and minimum heritability were obtained for chlorophyll (0.75-0.89) and stomatal conductance (0.2), respectively. The least phenotypic and genotypic coefficients of variation were observed for CO2 levels in boundary layer. Phenotypic and genotypic correlation coefficients between Chl a, Chl b and total Chl were similar and between SPAD Chl and Chl b were significantly high. Chl b content and transpiration rate, stomatal conductance and H2O levels in boundary layer had positive and significant genotypic correlation. CO2 levels in boundary layer and stomatal conductance were significantly and linearly associated with photosynthesis rate. 78.62% of data variation was explained by two factors. Genotypes in first group showed appropriate photosynthetic characters for resistance to drought and heat. Genotypes in third group have high chlorophyll content and photosynthesis rate. Maximum (103.19) and minimum (0.98) genetic distance was found betwee

Genetic analysis of grain yield, days to flowering and maturity in oilseed rape (B. napus L.) using diallel crosses.

Abstract Twenty one F 2 progenies derived from a 7×7 diallel crosses along with parents were evaluated for grain yield, flowering and maturity time. Due to significant genotypic effects for all traits, genetic analyses were performed on F 2 progenies including analyses of combining ability and genetic components. The Analysis of variance revealed that both additive and non-additive genetic effects were involved in controlling these traits. GCA/SCA ratios were 0.91 for days to flowering, 0.95 for days to maturity and 0.83 for grain yield which indicated that the additive gene effects were more important than non-additive gene effects for all these traits. Narrow-sense heritability was high for days to flowering (73.12%) and days to maturity (81.99%) and low for grain yield (30.15%). Heterosis in hybrids seemed to be largely determined by complementary epistasis as well as genetic distance between the parents. The spring-type varieties Tower and Regent appeared as the best parents for earliness whereas winter-type varieties D.R. and Ceres were best parents for high grain yield. It could be concluded from the study that S 1 recurrent selection would be effective to improve the performance of these genotypes for grain yield, flowering and maturity time. The selected S 1 lines from each cycle can be used in a pedigree-breeding program to identify superior genotypes

Genetic diversity of durum wheat genotypes using morpho-protein analysis

Knowledge of morpho-protein patterns of genetic diversity improves the efficiency of germplasm conservation and development. The objective of present study was to evaluate 116 genotypes of Triticum turgidum from seven countries in terms of morphological traits and seed protein banding patterns. The results showed highly significant differences among the genotypes for the traits. The correlation between grain yield and weight per spike was significant and positive, while the correlation between days to heading, length of peduncle and plant height was significant and negative. The factor analysis classified the traits in to four main groups which accounted for 74.4% of the total variability. Sixteen allelic compositions were identified in the genotypes for high molecular weight glutenin subunits. The three alleles were present at the Glu-A1 locus and 8 alleles at Glu-B1. The null allele was observed more frequently than the 1 and 2 alleles. Two alleles, namely 17 + 18 and 20, represented more frequent alleles at Glu-B1 locus. The genetic variability in Glu-A1and Glu-B1 loci were 0.42 and 0.81, respectively. The cluster analysis based on morphological traits and HMW-GS clustered the genotypes in to six and seven groups, respectively. The results indicated the presence of high genetic variability among the genotypes. Our findings suggest that the plants belong to different clusters can be used for hybridization to generate useful recombinants in the segregating generations, the genetics and breeding programs for improvement of durum wheat