Document Type : Research Paper
Authors
1
Dryland Agricultural Research Institute, Sararood branch, Agricultural Research, Education and Extension Organization (AREEO), Kermanshah, Iran
2
Department of Agronomy and Plant Breeding, Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran
Abstract
Using an appropriate breeding method for genetic improvement of quantitative traits mainly depends on the nature of gene action and heritablity. In order to estimate genetic parameters for agro-physiological traits in rapeseed, a generation mean analysis was counducted using the following three crosses; Opera×Dalgan (C1), Parade×Dalgan (C2) and Licord×RGS003 (C3). The parents, F1, F2 and BC1, BC2, RF1, RF2, RBC1, and RBC2 generations were studied for 13 traits. The parents and segregating populations cultivated under drought stress in a randomized complete block design with three replications at Dryland Agricultural Research Institute, Sararood, during 2016-2017 croping season. The results showed significant differences among ten generations for all traits including days to maturity (DM), plant height (PH), silique per plant, silique length (SL), seed per silique, 1000-seed weight, leaf water content, chlorophyll content, electrolyte leakage, leaf temperature, plant yield, seed oil content (SOC) and harvest index in three crosses, indicating genetic differences between the parental genotypes. The highest level of best- and mid-parent heterosis was observed in F1 (229 and 300%, respectively) and RF1 (255 and 322%, respectively) generations for plant yield in C3. In addition to the additive-dominance model, mean generation analysis and joint scale test showed that epistatic effects are important for all the traits except silique length. The broad- and narrow-sense heritability of the traits in the crosses ranged from 0.26 to 0.98 and from 0.08 to 0.67, respectively. This study revealed that dominance variance has the most important genetic effect in controlling of all the studied traits except for DM and SL in three crosses, PH in C1 and C2, and SOC in C2 and C3.
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