Comparison of yield, cob characteristics and sensory quality of six supersweet (sh₂) corn cultivars grown in a subtropical environment

Abstract

Yield and cob characteristics of 6 supersweet corn (Zea mays L.) cultivars, homozygous for the recessive shrunken-2 (sh2) allele, were compared at 3 separate planting dates, in 1987-88, at Bundaberg (lat. 25¦S.), Queensland. Sensory quality of the 6 sh2 cultivars and a standard cultivar, homozygous for the recessive sugary (su) allele, were compared in a separate experiment. Marketable yield (total weight of cobs-in-husks with at least 125 mm usable kernels without damage or defects) declined between each of the plantings: midwinter, early spring, late spring. Marketable yield of the cultivar Sucro was consistently high (9.18-13.7 t/ha), whereas, that of Honey Sweet was low (2.88-5.43 t/ha). Total weight of unmarketable cobs (cobs-in-husks with 125 mm usable kernels or cobs-in-husks having at least 125 mm usable kernels, but with damage or defects) was highest for Honey Sweet and ranged between 5.31 and 9.18 t/ha. Marketable yields of the 6 sh2 cultivars were similar to those obtained in other warm climates but were lower than those in cooler climates. The cobs-in-husks of Honey Sweet and Sucro from the midwinter planting were marginally heavier than the preferred cob-in-husk range (310-360 g/cob) demanded on domestic markets; those of Snosweet, Candy Sweet and Florida Staysweet were within the range; and those of Sugar Sweet were significantly (P<0.05) lower. None of the cultivars at the 2 later sowing dates achieved this desirable weight range. Because of the higher yields and larger cobs produced in the midwinter planting, and the higher incidence of disease and heat stress encountered in the later plantings, it is proposed that sh2 cultivar production should be limited to a midwinter sowing in subtropical Bundaberg. Taste panel testing indicated preference for all sh2 cultivars over the standard su cultivar in terms of both general acceptability and texture (P<0.05), and the su cultivar was rated least sweet (P<0.05). Snosweet was rated highest in terms of both general acceptability and texture scores and was also rated the sweetest cultivar.