|Head Rice Improvement-90
Project Leader and Principal UC Investigators
Shu Geng, professor, Dept of Agronomy & Range Science, UC Davis
Richard MacGregor, graduate student, Dept of Agronomy & Range Science, UC Davis
This project focuses on the methods and technology needed to improve
California head rice of the three main grain types. Its purpose is to
enhance the understanding of the fundamental characteristics of the heredity
of milling quality. This information will facilitate breeding efforts to
improve head rice yield for California rice.
The 1990 research continued to assess the heritability and coheritability of 24 short grain, 23 medium grain and 24 long grain lines. The characteristics under investigation are head rice yield for different portions of the panicle, seed dimensions and weight, panicle length, number of seeds per panicle and number of blanks per panicle.
Heritability values have been determined for panicle length, panicle moisture content, seed length, breadth, width, weight, volume and density, as well as for head rice yield at different harvesting dates for the top, middle and bottom portions of the panicle. Observations agree with previous studies.
Generally, the heritability of panicle and kernel characteristics is very high and the heritability of milling quality is lower than the other traits. In all cases, the heritability rapidly decreases with progressive generations. There seems to be no significant difference in heritability estimates between stressed and non-stressed environments.