The effect of moisture stress on flower and pod abortion, and seed yield components in lentils (Lens culinaris L.). A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science (Hons.) in the University of Canterbury

Abstract

Four levels of moisture stress were imposed on lentils (Lens culinaris, cv Titore). Plants were grown in a glasshouse. Moisture treatments were pots allowed to dry to 87.5%, 75.0%, 62.5% and 50.0% of field capacity before being rewatered to field capacity. Plants were grown at low moisture stress until flowering. Increased moisture stress had no significant effect on plant dry matter production, seed yield or HI. However, seed yield and HI appeared to decline with increased moisture stress. Maximum seed yield and HI was 0.866g and 35.4% respectively, at high moisture status. Main stem vine length (555 mm) and internodal distance (16.1 mm) were not affected by increased moisture stress. The number of reproductive nodes, and the position of the first and last flower and pod, was not affected by increased moisture stress. Flowering commenced at node 22 and finished at node 33. The first and last flowering nodes generally produced mature pods. Plants grown at high moisture status and severe moisture stress had the greatest number of flowers, immature and mature pods per node. There was a significant quadratic response in the number of flowers and immature pods per node, but no relationship between the number of mature pods per node, with increased moisture stress. Of the flowers that reached anthesis 28% aborted before forming pods, and of the immature pods, 23% aborted before maturity. Increased moisture stress had no effect on seeds per pod, although mean seed weight declined. There were 1.2 seeds per pod, and the mean seed weight ranged from 20.15 mg to 27.43 mg. There were no significant water-node number interactions. There was a highly significant quadratic relationship between the mean number of flowers, immature pods, and mature pods per node and node number. At node 22, 1.67 flowers formed, 1.33 immature pods, which gave 1.21 mature pods. These all fell to 0.08 by node 40. The number of aborted flowers and pods decreased as node number increased. The number of seeds per pod declined slightly with increased node number. Mean seed weight was not affected by increased node number until node 37. Above this, mean seed weight fell dramatically. The mainstem cumrnulative yield was 224.6 mg.