Pakistan Research Repository


Ansari, Bashir Ahmed (2003) DIALLEL ANALYSIS OF YIELD AND YIELD COMPONENTS IN TRITICUM AESTIVUML. PhD thesis, Sindh Agriculture University, Tando Jam.



Bread wheat (Triticum aestivum L) varieties Pavon, C 591, M 154, Jauhar 78, Blue Silver and ZA 77 were used as parent material in a set of 6*6 diallel crosses. Thirty combinations were obtained, 15 from direct crosses and 15 from reciprocals. The seed was harvested from a hand emasculated spikes of female parents. The parent material and their F1 and F2 hybrid populations were evaluated for plant height, number of tillers per plant, main spike length, number of spikelets per spike, number of grains per spike, seed index (100 seed weight) and grain yield per plant in two separate fertilizer environmental sets (E I and E II). The experimental data were evaluated / assessed for hybrid vigour and for their significant level in F1 generation. The entire data in F1 and F2 generation along with their parents for all the parameters were subjected to diallel analysis. Combining ability analysis was performed according to Griffing s model. The genetic component of variation was determined and the interactions were interpreted. The gene action assessed of various components was supplemented with Wr/Vr graphs in both the generations (F1 and F2) under the set of environments. The mean squares indicated that parental lines and their hybrid populations in F1 and F2 generations were significantly different (p 0.01) for all the seven traits under study grown under both the environments. It was noticed that almost all the F1 hybrids displayed relative heterosis and heterobeltiosis in grain yield per plant to the extent of 82.96% and 78.50% (E II) due to positive contribution of primary yield components such as number of tillers per plant, number of grains per spike and main spike length. It was further observed that 93% of F1 hybrid population exhibited superior heterosis over better parent at E I and 87% at E II for grain yield per plant. Moreover, 9 hybrids at E I and 24 hybrids at E II for grain yield per plant. Moreover, 9 hybrids at E I and 24 hybrids at E II signified the highest level of heterobeltiosis in this regard. The positive heterosis for the character tallness was recorded in the combinations which involved C 591 as one of the parent and negative heterosis was observed in the combinations having Blue silver as common parent. Furthermore, high fertilizer dose affected adversely the tallness of plants and thus resulted in the reduction in culm length. Present findings suggest the exploitation of the F1 hybrids of Blue silver x ZA 77, Blue silver x C 591 and Blue silver x jauhar 78 at low fertility regime while, Jauhar 78 x Pavon, Jauhar 78 x Blue silver and their reciprocal at high fertility regime which obtained maximum benefit for heterosis and heterobeltiosis for grain yield and its main components in F1. General combining ability and specific combining ability ratio indicate that both additive and non additive genes were more ascertained. Therefore both the sources can be utilized for the improvement bread wheat genotypes. Among the six involved parental lines, Jauhar 78 was found to be good general combiner for tillers per plant, main spike length, spikelets per spike and grain yield per plant. For the trait seed index Blue silver showed the highest GCA effects and their mean values may be taken as criteria while planning the hybridization programme involving these genotypes. The hybrid of Blue silver x ZA 77 and its reciprocal Blue silver x C 591, Pavon x C 591, and Jauhar 78 x Pavon showed high GCA effects on grain yield and also on its main components which exhibited superior per se performance and are recommended to form the basis of selection. Such combinations will provide the promising source for the evolution of high yielding bread wheat genotypes. The results of genetic components of variations suggest that the selection of transgressive sergeants on the criteria of number of tillers per plant, number of grains per spike, seed index and grain yield per plant could be made at an early stage. Whereas, for the traits plant height, main spike length and number of spikelets per spike the selection of desirable hybrids could be delayed and may be done in subsequent generations.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Diallel analysis, Yield components, Triticum aestivum L, Bread wheat, Pavon, C 591, M 154, Jauhar 78, Blue silver, ZA 77, Diallel crosses, emasculated spikes, F1, F2, Hybrid population, Plant height, Tillers per plant, Spike length, Spikelets per spike, Grains per spike, Seed index, Grain yield, E I, E II, Hybrid vigour, Griffing s model, Heterobeltiosis, Heterosis, Bread wheat genotypes, Transgressive segregants,
Subjects:Agriculture & Veterinary Sciences(a)
ID Code:70
Deposited By:Mr Ghulam Murtaza
Deposited On:16 Jun 2006
Last Modified:11 Jun 2008 21:55

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