Genetically diverse female lines of sunflower were crossed with male testers to get heterotic hybrids. Studies were carried-out during 2008-2010 at Experiment filed of Agriculture Research Institute, Tandojam, Sindh, Pakistan. Six female lines like T-4-0319, PAC-0505, HO-I, Hysun-33, Peshawar-93 and CMS-03 and three testers i.e., PAC-0306, PAC-64-A and SF-187 were crossed in a line ´ tester mating design, thus 18 F1 and F2 hybrids were developed for evaluation of heterosis and inbreeding depression for days to initial flowering, days to maturity, leaves/plant, plant height (cm), head diameter (cm), 1000-achene weight (g), seed yield kg/ha and oil yield kg/ha. The experiment was conducted in a randomised complete block design with four replications. The analysis of variance revealed significant differences among parents, F1s and F2 hybrids for all the traits studied. The existence of significant genetic variability among the plant traits is particularly useful because variations in these traits would allow further improvement in sunflowerseed yield and oil traits. The F1 hybrids HO-I ´ PAC-0306 and HO-I PA ´ C-64-A exhibited desirable negative mid and better parent heterosis for days to initial flowering, days to maturity and plant height. These hybrids also manifested desirable positive heterotic effects for leaves/plant, head diameter, 1000-achenes weight, seed yield and oil yield. Inbreeding depression for phenological, seed yield and oil traits showed that desirable high inbreeding depression was observed in hybrids HO-I ´ P´AC-64-A, HO-I ´ PAC-0306 and HO-I ´ SF-187 for days to initial flowering, similarly T-4-0319 ´ PAC-0306, PAC-0505 ´ SF-187 and HO-I ´ PAC-64-A explicated maximum but rewarding inbreeding depression for days to maturity. The F2 hybrids Hysun-33 ´ SF-187 and Peshawer-93 ´ PAC-64-A may be the most desirable ones in the sense that they recorded comparatively moderate inbreeding depression with enough number of leaves to be productive if F2 hybrids are to be exploited for hybrid vigour. Low inbreeding depression for various traitsindicated that such hybrids some how favour the usefulness of F2 hybrids in sunflower.
The seed of five parental cultivars alongwith their 10 F 1 hybrids of wheat were sown in a randomized complete block design with four replications during 2010 at Sindh Agriculture University, Tandojam, Pakistan. Genetic analysis of yield traits from half diallel crosses was carried-out. Mean squares due to GCA and SCA were significant for days to 75% maturity, tillers plant -1 , spike length, spike density, grains spike -1 , grain yield plant -1 , seed index and harvest index. Significance of GCA and SCA variances suggested that both additive and non-additive genes were controlling these characters. The magnitude of SCA variances were higher than GCA indicating pre-dominance of non-additive gene effects for spike length, spike density, seeds spike -1 , grain yield plantand harvest index, while GCA variances were greater for days to 75% maturity, tillers per plant. Parental cultivar TD-1 expressed maximum GCA effects for tillers plant -1 , spike length, grain yield plant -1 , seed index and harvest index; while negative and desirable GCA for days to 75% maturity. The SCA estimates revealed that F 1 hybrid TD-1 × TJ-83 manifested maximum SCA effects for tillers plant -1 , spike length, grains spike -1 and negative yet desirable for days to 75% maturity. The cross TJ-83 × Sarsabz recorded with higher estimates for grains spike -1 , grain yield plant -1 , seed index and harvest index. Thus both the F 1 hybrids may be choice breeding material for hybrid crop development to improve the yield traits.
Development of wheat varieties with low moisture requirements and their ability to withstandmoisture stress may cope-up well with the on-coming peril of drought conditions. Ten wheat genotypesincluding two new strains, PBGST-3, Hero, Bhittai, Marvi, Inqlab, Sarsabz, Abadgar, Kiran, Khirman andPBGST-4 were sown in split plot design with factorial arrangement in four replications at ExperimentalField, Department of Plant Breeding & Genetics, Sindh Agricutlure University, Pakistan during 2012-13.The results revealed that water stress caused significant reductions in all morpho-physiological traits. Thegenotypes differed significantly for all the yield and physiological traits. The interaction of treatments ×genotypes were also significant for all the traits except plant height, productive tillers/plant, grains/spikeand harvest index, were non-significant which indicated that cultivars responded variably over the stress treatments suggesting that breeders can select the promising genotypes for both stress and non-stressenvironments. Among the genotypes evaluated Bhittai, Kiran-95, PBGST-3 and Sarsabz showed goodperformance as minimum reductions occurred under terminal stress conditions for all the traits studied.Hence, above mentioned genotypes were considered as drought tolerant group. The high positive correlationsof physiological traits like chlorophyll content and relative water content with almost all yield traits indicatedthat these physiological traits could serve as reliable criteria for breeding drought tolerance in wheat. Thenegative correlations of electrolyte leakage with several important yield traits indicated that though thisphysiological trait has adverse effect on yield attributes, yet it could reliably be used to distinguish betweendrought tolerant and susceptible wheat genotypes.
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