Characteristics and inheritance of nonsenescence in Sorghum bicolor (L.) Moench

Abstract

Three coverted lines (SC0056, SC00599, and SC0170) from the sorghum conbersion program remained green and vigorous in the field at grain harvest time when "normal" sorghum types senesced and apparently ceased functioning physiologically. This phenomenon has been termed nonsenescence. The objectives of this initial study were twofold: 1) to compare the senescing and nonsenescing types for various plant characteristics in the hope of ascertaining which particular physiological characteristics may be associated with nonsenescence, and 2) to determine the inheritance of nonsenescence in sorghum. Various plant characteristics were evaluated for three summers, 1974 to 1976, and included growth parameters, yield and yield components, axillary and basal tiller production, stem diameter, percent stem sugar concentration, and green leaf blade chlorophyll content. The evaluation study was planted in 5- or 7-row plots with four replications in a randomized complete block design. Row spacing was 68 cm while plant population was either 123,550 or 148,260 plants per hectare. Growth data were recorded during the reproductive phase of development (boot stage to harvest) from the second and fourth rows of the plot; yield data, from the middle row of each plot.