ONION HYBRIDS: EVALUATION, PROSPECTS, LIMITATIONS, AND METHODS
In the author's view, low priority should be given to breeding onion hybrids for the tropics while high priority should be given to the following:
- collection, multiplication, and evaluation of a wide spectrum of tropical onion strains;
- selection for improved characters in promising strains;
- combining complementary promising strains and subsequent selection in resulting composites;
- addition of individual superior characters from nonadapted varieties and closely related species;
- improvement of multiplication methods for the central tropics (from 10° N - 10° S).
In the meantime, well-equipped institutions in or close to the subtropics (e.g., AVRDC and/or Rahuri) could pave the way for local hybrid breeding in the near future by:
- analyzing tropical strains for frequencies of S, N, ms, and Ms genes; and
- testing the male sterility in question for its thermostability in tropical conditions.