Mar 13, 2017

Breeding & Genetic improvement WCRC Breeding-Australia WCRC1
Abstract                                                                         Back to Table of contents

Research on F1 cotton hybrids in Australia has produced some promising examples of heterosis but results have been inconsistent.  Given the difficulties of F1 seed production, little research has been conducted in recent years.  However recent research and commercial development in the USA have generated interest in F2 hybrids, particularly with the advent of chemical sterilants.

Two high performing cultivars from the USA  and four from Australia were crossed and the six parents and 15 F2’s were grown under irrigation at two sites in northern NSW in the 1991/92 and 1992/93 seasons and at three sites in 1993/94.  At one of the sites in the first two years the 15 F1’s were also included.

Over the two environments the F1’s averaged 10% more than the parents with the largest advantage (15% higher yield) coming in a lower yielding Verticillium wilt affected trial.  Over the seven environments the F2’s averaged only 3% greater yield than the parents and the best F2 did not significantly outyield the best commercial cultivar.  In the three highest yielding trials the F2’s did not outyield the parents but in the four lower yielding, Verticillium or rain-affected trials the F2’s averaged 6% more.  No commercially important effects were found for fibre quality for the F1’s or F2’s.

The low level of heterosis at the high yielding sites is in accord with previous Australian results and, given the difficulties of F1 hybrid seed production, suggests that at present the only possible uses for hybrids may be with F2 hybrids in lower yielding disease prone or raingrown situations.

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