Abstract
Autotetraploid rice is an important germplasm and has a great scope to increase rice yield but low seed set is a major
encumbrance in its utilization. The present study was planned to observe the cytogenetic and agronomic characteristics of
newly developed highly fertile autotetraploid rice line (1162). Agronomic traits, male and female gametophytes of newly
developed autotetraploid rice (1162) and their hybrids showed better performance as compared to its parents and other
autotetraploid rice lines. The mean of panicle length, number of grains per panicle, filled grains per panicle, 1000-grain weight,
grain length, grain width, and seed set were 25.04cm, 103.38 grains, 83.56 grains, 43.44g, 9.54mm, 4.04mm and 81.58%,
respectively. The meiotic analysis showed that the mean meiotic configurations of 1162 at diakinesis were (0.13±0.05) I +
(4.89±0.26) II +(0.02±0.00) III +(9.45±0.13) IV. The frequency of trivalent and univalent in new line was lower than the
autotetraploid lines (control) at diakinesis and metaphase I, and the configuration of chromosome in 1162 was more
symmetrical, which was in favor of 2/2 segregation of homologous chromosome, although higher number of quadrivalents
were found than parents. Heterosis of hybrids crossed with 1162 was not only positive but also attained highly significant
levels for important quantitative traits. The results showed that high fertility can be inherited and have important applications
and research value.
