generations mean analysis

Grain yield, physiological and phenological traits in seven generations of maize using the generations mean analysis method under controlled conditions and, moderate and severe water deficit stress were studied. Evaluation of the generations drived from a cross between two inbred lines of maize including B73 and MO17, SC704 (as F1 generation), F2, BC1, BC2 and F3 using a randomized complete block design with 20 replications was conducted during two crop years of 2018-2019 at the Agricultural Research Station of University of Tabriz. The results of combined analysis of variance and mean comparisons of data under three different irrigation regimes showed that water deficit stress significantly reduced grain yield and physiological traits, and a significant increase in phenological traits. Generation mean analysis showed a high contribution of non-additive gene effects in the genetic control of the studied traits. This indicated that the necessity of selection in advanced segregating generations and the production of hybrid varieties in maize to take advantage of the dominance variance. Also, the significant contribution of additive gene effects in controlling the inheritance of the number of days to silk emergence indicated that selection in early segregating generations and inbred parents can be effective for breeding of this trait and taking advantage of additive variance. Based on the studied traits, inbred line MO17 and hybrid SC704 compared to other studied lines showed high tolerance to water deficit stress (from 5-6 leaf stage to silk emergence) and had the grain yield stability.