Effect of Plant Growth Regulators on Reproduction of ‘Starr’ Spanish‐type Peanuts

Abstract

AbstractSuccessful use of plant growth regulants to increase yields of leguminous field crops has not been achieved. Only a few substances have been tested on peanut (Arachis hypogaea L.) plants. Four diverse plant growth regulators were tested on ‘Starr’ Spanish‐type peanut plants to 1) determine their effects on growth and yield components, 2) establish an optimum time for regulant application, and 3) ascertain any residual effects on germination of the seeds produced. The regulants were applied at either early or late‐flowering to plants grown in the greenhouse. When treatments were applied at early‐flowering, shoot fresh weight at harvest was reduced by morphactin, but increased by abscisic acid and picloram plus 2,4,5‐trichlorophenoxyacetic acid. None of the substances affected growth in the late‐flowering treatment. There was no apparent relationship between vegetative growth and weight of mature seeds produced.Cumulative flowering patterns were altered by some of the substances and the continuous, prolonged flowering of these indeterminate plants was prevented. Pegging was stimulated by morphactin, but there was a wide range within which flowering and pegging could proceed without significantly affecting yield.Treated plants produced seeds with altered germination. Seeds from morphactin‐treated plants germinated abnormally, and they had low ethylene production rates; the percentage of rapidly growing (vigorous) seeds was reduced. The percentage of vigorous seeds from plants treated with abscisic acid and 2.5 ppm of herbicide was also reduced.