Physiology of Oil Seeds: IX. Effects of Water Deficit on Peanut Seed Quality

The peanut ( Arachis hypogae L.) crop is frequently subjected to water deficit during the growing season. This study was conducted to determine the effect of water received by the crop on the germinability and vigor of the subsequent seed generation. Two peanut genotypes, ‘Comet’ and breeding line OK‐FH15, were grown under both rainfed and irrigated conditions on a Teller sandy loam (fine, mixed, thermic Udic Argiustoll) soil in 0.91‐m wide rows using standard agronomic practices. Pods were harvested, dried, and shelled. Only mature seeds(those with smooth seed coats and riding at least a 5.95 by 19.05 mm slotted screen) were used in the tests. Seeds were germinated at 29 ± 1 °C in 2‐L flasks fitted with two sheets of 15.0‐cm Whatman no. 5 filter paper. Ethylene and CO 2 were quantitatively determined by gas chromatography. Germination ranged from 94 to 100%, but was lowest for seeds produced under water deficit. Maximum C 2 H 4 production occurred at 22 to 24 h of germination during hypocotyl‐radicle emergence. Carbon dioxide production was maximized 24 h later, or rose slowly thereafter. Water deficit during seed production affected both C 2 H 4 and CO 2 production during subsequent germination. The most consistent response to water deficit was reduction in the fraction of rapidly growing seedlings (those with hypocotyl‐radicle longer than 20 mm at.72 h of germination. Thus, water deficit during seed development affects subsequent growth of seedlings and could pose a problem in establishment for the succeeding crop. A minimum of 500 mm of water was necessary to produce a crop of seeds with high potential for germination and a high proportion of vigorous seedlings.