ESTIMATION OF COMBINING ABILITY AND HETEROSIS IN WHEAT

Abstract

The study used a half-diallel mating fashion to identify combining ability (GCA and SCA) and heterosis of six 
wheat (Triticum aestivum L.) genotypes and their 15 F1 hybrids for morpho-physiological, yield, and yield
contributing traits. The present study was carried out in a randomized complete block design with three 
replications. The studied characters are heading days, maturity days, chlorophyll content, Plant height, 
Effective tillers plant-1, Total tillers plant-1, Spikes plant-1, Spike length, Filled spikelets spike-1, Unfilled spikelets 
spike-1, Grains spike-1, Thousand grain weight, Grain yield plant-1, Biological yield plant-1, and Harvest index 
Highly significant differences were observed among genotypes (parents and F1 hybrids) for all characters 
studied. The results also showed that the mean squares due to general (GCA) and specific (SCA) combining 
abilities were highly significant for all studied characters except harvest index, indicating the magnitude of 
both additive and non-additive gene effects in governing these traits. GCA/SCA ratios were greater than one 
for all characters except filled spikelets spike-1 and harvests index, indicating the dominance of additive gene 
effects, which play important roles in the inheritance of these characters. While the non-additive effect of the 
gene predominated in the inheritance of filled spikelets (spike-1) and harvests index, The parent BARI GOM-30 
emerged as the best general combiner for total tillers plant-1, filled spikelets spike-1, grains spike-1, thousand
grain weight, grain yield plant-1, and harvest index. Bari Gom-28 was the best general combiner for heading 
days and maturity days, and Sourav was the best for effective tillers plant-1, spikes plant-1, and biological 
yield plant-1. The cross BARI GOM-30  SOURAV was the best specific combiner for effective tillers plant-1, total 
tillers plant-1, spikes plant-1, and PRODIP  SOURAV for filled spikelets spike-1. Bari GOM-33   Sourav emerged as 
the best specific combiner for grain yield plant-1 and Prodip    Ayt-5 for grain spike-1. Concerning heterotic 
effects in comparison to the midparent, the F1 hybrid BARI GOM-28  BARI GOM-33 showed maximum 
significant positive heterosis for chlorophyll content and biological yield plant-1 and BARI GOM-33  SOURAV for 
effective tillers plant-1, spikes plant-1, and grain yield plant-1. These parents and cross combinations could be 
used for the breeding program of wheat for potential yield.