Variety Improvement for Better
Root Systems-82
 
 

Home.gif (3162 bytes)

Next.gif (3180 bytes)

Back.gif (3162 bytes)

Project Leader and Principal UC Investigators

Ivan Buddenhagen, Department of Agronomy and Range Science, University of California, Davis

 

Large differences were found in the ability of different genotypes to grow and flower under upland conditions. Some of the best materials were early maturing short-stature California varieties and several other lines from Korea, Egypt, Brazil and West Africa.

Varietal improvement for better root systems was a new project in 1982 made possible by the introduction of new sources of germplasm from some of the international research centers as well as from Brazil and Korea. These diverse sources included Japonica, Indica, and Javanica rices, many of which were upland types. Some of these were known to have unusually good root systems and lodging resistance.

The objectives were: 1) to screen these genetically diverse lines for performance under upland conditions, 2) to evaluate the growth of some of these lines under upland and f ooded conditions, 3) to compare the growth of rice, wheat and barley under upland conditions, and 4) to study iron uptake by rice plants under upland conditions. Iron is often deficient with upland rice culture. Upland culture for purposes of these studies consisted of a flushing surface irrigation every 10 to 14 days.

Large differences were found in the ability of different genotypes to grow and flower under upland conditions. Some of the best materials were early maturing short-stature California varieties and several other lines from Korea, Egypt, Brazil and West Africa. Some of the exotic lines also were not adversely affected by the very cool temperatures at Davis in 1982. These lines showed large differences in grain type, panicle size, lodging resistance and other characteristics. These lines help broaden the germplasm base for genetic and breeding programs.

 

Dr. Ivan Buddenhagen examines the performance of a world collection of rice lines grown under upland conditions at the Rice Research Facility, Davis.

In general, upland culture with periodic drought stress reduced height and delayed flowering by about two weeks. In most cases tillering was not reduced, and some genotypes were not delayed in flowering. Several segregating populations from earlier crosses survived drought conditions and remained alive with green leaves into December.

Comparisons were made at maturity of several varieties grown in rows under flooded and upland conditions. The early maturing California varieties in upland-type culture reduced plant heights by 30 percent, number of spikelets by 30 percent and grain yields by 40 percent. However, tiller and panicle numbers and percent filled grains were increased in two of three comparisons. A comparison of three traditionally tall varieties with their mutant short-statured derivatives resulted in generally superior performance of the short types under upland-type culture.

The comparison of upland-type culture for rice, wheat and barley did not produce valid data because of the ofd season planting date for wheat and barley. However, in a greenhouse experiment, two upland types of rice were as efficient in water use as wheat and barley.

Differences among rice varieties in ability to uptake and use iron were found, indicating fundamental differences in the nutrition of rice under aerobic root environments.

 

Home.gif (3162 bytes)Next.gif (3180 bytes)Back.gif (3162 bytes)