Tetraploids Induced in Rice by Temperature and Colchicine Treatments1

Abstract

Abstract: Naturally occurring haploid and triploid plants that arose as mutations in varieties and hybrids at the Texas Agricultural Experiment Station No. 4, Beaumont, Tex., are reported. Twenty-six tetraploid and eight tetraploid-sector plants were obtained from seed produced in panicles of the Blue Rose and Caloro varieties exposed, for certain periods, to low and high temperatures or a combination of both within 19 to 24 hours after blooming. Soaking Blue Rose seed in colchicine solutions produced three tetraploid plants in the second generation following treatment. Shoots of a haploid plant, untreated and treated in colchicine solutions, produced diploid and diploid-sector plants. Three cases in which haploid plants produced some seed are reported. Tetraploid and triploid Blue Rose and Caloro plants were not as tall, tillered less, were less fertile, and had coarser leaves and larger florets and seeds than diploid plants of these varieties; whereas, the haploid plants were completely sterile and were shorter, tillered much more, and had finer leaves and culms and smaller florets than the diploids.