Generation mean analysis for grain yield and its components in bread wheat (Triticum Aestivum L.)

Abstract

Generation means analysiS mvolving s1x generations of eight crosses of wheat (Tnttcum a~stt~um L.) was used to elucidate the extent of variability, association among ~ram y1eld an.d component traits. magnitude of heterosis and Inbreeding depression and mhentance of spike length, plant height, spikelets per spike. awn length, peduncle length, flag leaf area, specific leaf weight. effective tillers per plant, days to maturity, grams per spike, biological yield per plant, grain yield per plant, harvest index and 1 000-grain weight. Phenotypic and genotypic coeffioent of variation were high for specific leaf we1ght; moderate for flag leaf area, gra1n y•eid per plant. harvest index. tillers per plant. btologtcal yield per plant, sp1ke length and peduncle length whereas, these were low for awn length, 1()()().gratn weight, number of grains per spike. spikelets per sptke, plant height and days to maturity. High heritability coupled with high genetic advance was observed for flag leaf area, specific leaf weight, biological yield per plant, grain yield per plant and harvest index showing the influence of additive gene action on these tratts and hence may prove useful for effective selection Seed y1eld per plant exhibited s1gntficant and strong posttive assoctalton with effecttve tillers/plant, harvest index. grains/spike, 1 ()()().grain weight. biological yield per plant, spikelets/spike and specific leaf weight. Htgh positive and direct mfluence of harvest tndex followed by biological yield per plant, effective tillers per plant, grains per sp•ke and 1000 gratn weight towards grain yield per plant was noticed. For grain yield the best five crosses reported in the present study are PBW 502 X 11th HRWYT 16, PBW 343 X CPAN 3004, RD1008 X PBW 373, and PBW 502 X RD1008 and UP 2338 X PBW 343 as these had highly significant and positive heterosis over mtd parent tndicating overdommance for high gra•n yteid. The relationship between heterotic response and inbreeding depresston Indicated that tn almost all the crosses showing htgh heterosis in F, also showed high inbreedmg depression in F2 for all the characters indicating the importance of non-addtllve gene action in wheat. The gram yield per plant and •ts component trans were mostly governed by the addttive, dominance and eptstaltc ty~ of gene effects but were unexploitable due to duplicate type of gene action. Simultaneous utilization of both additive and nonadditiv~ gene~cts can be ach1eved by intermating of segregants In early segregatmg g~'\~on.