The Maturity Genes of Sorghum

Abstract

Publisher Summary This chapter discusses the maturity of gene loci of sorghum that influence floral initiation. It appears to be a part of the floral regulatory system. The time of floral initiation is controlled by four gene loci. Tropical varieties are dominant at locus 1 and usually at the other three loci also. Temperate zone varieties are recessive at locus 1, or, if dominant at locus 1, are recessive at either locus 2 or 4. The expression of the four genes is influenced by environment, particularly by photoperiod and temperature. The faster or slower floral initiation depends on the maturity genotype of the variety being grown. Dominant and recessive alleles at the four gene loci have important interactions that influence the time of floral initiation. When locus 1 is dominant, dominance at the other three loci causes lateness. When locus 1 is recessive, dominance at locus 2 or both loci 2 and 3 causes earliness. Heterozygosity at locus 1 has an unexpected interaction. Late floral initiation occurs when locus 1 is heterozygous and locus 2 is recessive. If locus 2 is dominant, heterozygosity at locus 1 does not delay floral initiation. Heterozygosity at loci 2, 3, and 4 has no apparent effect on the time of floral initiation.