Influence of parent and temperature during pollination on alfalfa seed weight and number of seeds per pod

Abstract

Alfalfa seed weight and number of seeds per pod are important characteristics which have been associated with seed yield and seed quality. The objective of this research was to investigate the relative influence of seed and pollen parents and temperature during pollination on individual seed weight and number of seeds per pod. The relative influence of seed position in the pod on seed weight was also investigated. Twelve diverse clones were designated as seed (4) and pollen (8) parents. They were grown in the greenhouse at 24/18 day/night temperature and then transferred to growth chambers which were maintained at either 18 or 27 °C during and 24 h after pollination. Seed weight and number of seeds per pod were influenced by temperature during pollination, and also by both seed and pollen parents. The position of the seed in the pod influenced seed weight. The largest seed occurred at the base of the pod, which may have resulted from a differential nutrient supply from the base to the top of the pod. The number of seeds per pod was greatest at 27 °C. This was attributed to enhanced pollen fertility and fertilization success at the higher temperature. Both seed and pollen parents influenced seed weight and number of seeds per pod, and there were significant seed × pollen parent interactions for both traits. Environmental influence and pod position effects on seed weight and number of seeds per pod were small when compared with genetic effects. Selection for seed characteristics in seed and pollen parents could improve alfalfa seed production and seed quality. Key words: Alfalfa, Medicago sativa L., seed weight, number of seeds, temperature during pollination