Combining ability of anther culture response in some rice crosses under drought stress conditions

Abstract

Anther culture response of ten rice parental genotypes and their 24 F1 crosses was studied to estimate combining ability effects for callus induction and plant regeneration under drought stress conditions. The analysis of variance showed that drought stress levels mean squares were found to be highly significant for all in vitro studied traits. The percentage of anthers that developed calli ranged from 12.92% for the IRRI 148 to 45.00% for the cross L1 × T3 among the genotypes across the four different stress levels of PEG. The control (PEG-free medium) gave the highest mean value of callus induction (41.33%). On the other hand, the medium containing 30 g/l of PEG gave the lowest one (14.28%) across all genotypes. Results showed that the three crosses (L1 × T2, L1 × T3 and L3 × T1) gave the highest mean values of plant regeneration (9.50%, 8.00 and 7.92% respectively). The percentage of plant regeneration from the control medium was 7.12%, while the medium containing 30 g/l of PEG gave the lowest one across all genotypes (3.76%). The ratio of GCA/SCA was found less than unity for all in vitro studied traits under the four stress levels, revealing the predominant role of dominance gene action in the inheritance of these traits. Results showed that the IRGC (T3) followed by Giza 177 (L1) were the best combiners for callus induction under varying concentrations of PEG due to their highly significant positive GCA values. For plant regeneration, one parental genotype Giza 177 (L1) was the best combiner for plant regeneration under varying concentrations of PEG due to their highly significant positive GCA values. The two crosses; L3 × T1 and L1 × T2 recorded the highest SCA effects for plant regeneration and green plant regeneration under the four stress levels.