TRIPLE TEST CROSS ANALYSIS FOR DETERMINING GENE ACTION, GENETIC CORRELATIONS AND PREDICTION FOR YIELD AND YIELD COMPONENTS IN BREAD WHEAT

Abstract

In two crosses of bread wheat (Gemmeiza11 x Misr1 and Gemmeiza12 x Misr2) to investigate gene action, genetic correlations and predicating new recombinant lines for days to heading, plant height, flag leaf area, number of spikes/plant, number of grains/spike, 1000-grain weight, spike grain weight and grain yield /plant, triple test cross was used. The starting materials for triple test cross was the F1 and their grand parents (P1 and P2) for the two studied wheat crosses. The first cross Gemmeiza 11 x Misr1 and the second cross was Gemmeiza 12x Misr2. The F1’s were selfed to produce F2’s grains. In order to create F1 and F2 plants, the obtained materials (F1 and F2 grain genotypes) and the parental genotypes were seeded together. Thirty individual F2 plants were randomly labeled from each cross and crossed back to their grand parents (P1 and P2) and F1 between then to produce three types of families L1 (F2i x P1i), L2 (F2i x P2i) and L3 (F2i x F1i) in each cross. On November 10, 2018, during the winter growing season, the triple test cross families (L1, L2 and L3), along with the parents, F1 and F2 in each cross, were seeded. Results showed that in the genetic system for the investigated features for two crosses, epistatic gene effects were significant. The types of epistasis (additive x additive, additive x dominance and dominance x dominance) were significant for all studied characters. For the majority of traits in both crossings, both additive and dominant genetic components were significant and involved in the genetic system. The average level of dominance for spikes/plant in cross 1 and spike grain weight in cross -2 was overdominance, while for the remaining characters, additive gene effects were more pronounced. The F value was positive and significant for 1000-grain weight in two crosses, suggesting that dominant genes controlling these characters were unidirectional. The highest proportion of inbreds excepted to outperform parental rang in cross 1 for days to heading and flag leaf area. In both crosses, grain yield per plant was positively and significantly correlated with number of spikes per plant, number of grains per spike, and 1000-grain weight, according to epistasis, additive, and dominance genetic correlations.