Abstract:
Fifty maize inbred lines were screened at seedling stage under drought and normal
conditions for various seedlings parameters under controlled conditions in growth
chamber, three drought tolerant and three susceptible inbred lines were selected.
These six genotypes were crossed in full diallel fashion. F 1 seed was planted in the
field using randomized complete block design in three replications under drought
and irrigated conditions. All the cultural and other practices were kept uniform to
both plantings except irrigation. Various agronomic and physiological parameters
were recorded. There was 20 to 40% reduction in almost all parameters was
observed. Co-efficient of variability was more under water stress than normal for
most of the seedling traits. In field experiment, additive gene action with partial
dominance was revealed for plant height, leaf area, leaf number, biological yield,
harvest index, stomatal frequency and stomata size under both conditions. Over-
dominance type of gene action was found for kernels per ear row, 100-grain
weight, leaf temperature and cell membrane thermostability. Additive gene action
for relative water content under normal condition was changed to over-dominance
under water stress condition. The best combinations on the basis of mean
performance under normal condition were Y-74×F-141, Y-74×F-128, Y-74×Y158
F-128×Y-158. Under water stress condition best performing crosses were, Y-
74×F-141, Y-158×Y-74, F-128×Y-74 and F-141×B-34. These crosses might be
useful as transgressive segregants in subsequent generations. Inbred lines Y-74
and F-141 were found best parents. These inbred lines may be exploited in future
breeding programme for drought conditions. On the basis of different inheritance
pattern of each parameter, it was suggested that overall performance of the inbred
lines and their all possible combinations might be more useful while selecting for
water stress condition.
