19. Studies on trisomics developed from a Chinese rice cultivar, Guangluai 4

Guangluai 4, an Indica variety of rice, is grown along the Yangtze river basin. Induced tetraploids of this variety were crossed with diploids and triploids were obtained. The spikelet fertility of various triploid plants ranged between 0-6.3% with a mean of 2.95%.

A progeny of triploids consisting of 114 plants was grown. It consisted of 6 diploid plants (5.3%) and 108 aneuploid plants (94.7%), including 38 plants with 25 chromosomes (33.3%), 19 plants with 26 (16.7%), 24 plants with 27 (21.1%), 15 plants with 28 (13.2%) and a few plants with 33,34 or 35, but the aneuploid plants with more than 30 chromosomes were malformed and sterile. The outstanding features of each trisomic are enumerated as follows:

Triplo-1 is grassy. Triplo-2 has longer empty glumes. Triplo-3 has long awns. Triplo-4 is sterile. Triplo-5 has twisted leaves with fine hairs. Triplo-6 has degenerated spikelets at the tips of panicle, Triplo-7 has semirolled leaves and incompletely exserted panicles. Triplo-8 has rolled leaves and shortened grains. Triplo-9 is stout with big grains. Triplo-10 has fine foliage and stems. Triplo-11 is pseudo-normal. Triplo-12 is the tallest among the trisomics and the disomics, which is very conspicuous. These observations agree with those reported by Khush et al. (1984).

Khush, G.S., R.J. Singh, S.C. Sur and A.L. Librojo, 1984. Primary trisomics of rice: Origin, morphology, cytology and use in linkage mapping. Genetics 107: 141-163.