Gene action for some agronomic traits in maize (Zea mays L.)

Results indicated over-dominance gene effects for days from silking to physiological maturity, days from anthesis to physiological maturity, plant height, kernel depth, number of rows per ear and grain yield. The most appropriate strategy for the exploitation of these effects is to obtain hybrid cultivars and evaluate these characteristics in hybrid combinations. The gene effect for days from emergence to physiological maturity and number of kernels per row was complete dominance, suggesting that reciprocal recurrent selection would be effective. Ear leaf area and ear length were controlled by partial dominance, indicating that additive gene effects were more important than non-additive gene effects for controlling the inheritance of these traits. Therefore, improvement of these traits through selection of breeding materials is highly feasible. Broad-sense heritability ranged between 47.4% and 89.4% for days to physiological maturity and number of rows per ear; however, narrow-sense heritability varied between 7.3% and 50.6% for days from anthesis to physiological maturity and ear leaf area, respectively. Non-additive gene effects were predominant for controlling the majority of traits

Influence of salinity on the germination of Iranian alfalfa ecotypes

Nineteen ecotypes of alfalfa (Medicago sativa) from Iran were evaluated for their salt tolerance based onresponses of their seed germination with increasing salinity levels. Seeds of alfalfa were obtained fromvarious parts of Iran under diverse climatic zones. The study was conducted at Putra MalaysiaUniversity during March 2008. Seeds were placed in petri dishes on filter papers immersed in solutionswith six levels of salinity (0, 50, 100, 150, 200 and 250 mM) using sodium chloride as the salt. Data onseed germination performance were observed over a period of 20 days. Results showed that there weresignificant effects of salinity levels, ecotypes, and interaction between salinity and ecotype ongermination percentage, germination rate and germination index. Reactions of ecotypes to salinitylevels relative to all germination parameter were variable so that there are wide ranges of salt tolerancebetween the ecotypes. Ecotypes originating from the arid and cold areas were more tolerant than otherareas