Calag Archive

Chemicals now available will apparently control watergrass and some broadleaved weeds, if properly used. Another group of chemicals including MCPA and 2,4-D are 3xtremely effective against the broadleaved weeds. Good crop rotation systems, use of weed-free seed, water management and many other well known riceland management practices are also still available to rice farmers fighting weeds. With proper use of these new chemical tools far weed control, growers could be at the threshold of a new era of rice culture.

IN THE CALIFORNIA varietal improvement program: the main objectives are the development of non-lodging, short-, medium- and long-grain varieties, which emerge well through the cold water of the sowing season, which have a high yield and meet the required milling and cooking characteristics. Joseph R. Thysell, Research Agronomist, CRD, ARS, heads the USDA rice-breeding project at the Rice Experiment Station, Biggs, as reported separately in this issue. The breeding program was intensified and expanded in 1961 with the appointment of a rice breeder by the California Rice Research Foundation. This is a report on phases of the rice breeding project for which the Foundation has principal responsibility.

EST DAMAGE to rice plants in California most frequently occurs during the first two months of the growing season. This injury is generally caused by the tadpole shrimp, the rice leaf miner, and the rice water weevil. The first two pests are found throughout the rice-growing areas of the State. They may be responsible for a reduction in plant stand from April to June but their activity is greatly reduced or of little consequence by early July. The rice water weevil, presently limited to the northern rice growing counties, will feed on the rice plants during the entire growing season. This weevil very seldom causes a loss of plant stand, but the feeding of the young on the roots may stunt the plant and reduce the yield if the larvae are abundant.

ONE OF THE important considerations in the development of any new rice variety is its optimum range of seeding dates. The response to seeding date of present commercial rice varieties in California is well known, hut must be determined for new and introduced varieties. The commercial rice crop in California is sown directly into the water. In the past, however, the rice-breeding nurseries have been drilled rather than water-seeded. Recent studies have demonstrated that rice sown directly into the water produces higher yields than rice that is drilled.

Japonica rice is grown in the Central Valley of California primarily on dense clay soils under continuous flooding. Nitrogen is usually insufficient in these soils for optimum rice production, and nitrogen fertilization increases average yields about 40%. In some instances, nitrogen and phosphorus together are essential for optimum yields. Potash and other nutrient elements are usually adequate.

The genetic constitution of flax plants determines the quantity and quality of oil produced. However, both of these seed characteristics are strongly influenced by environment, as reported in these analyses of flaxseed grown in different locations in California.

Only seven known avocado root rot infestations have been located out of the 450 acres of avocados grown in Riverside County, and of these, only one grove has been extensively damaged. As previously reported from preliminary results of the statewide survey, this Riverside study also showed that root rot damage is dependent on the introduction of the fungus P. cinna-momi in soils with poor internal drainage. However, even with the best soils, the rate of spread can be increased with excessive soil moisture.

Neither yield nor seed size increases when Dark Red Kidney beans are cut after the average moisture content has reached 50%, according to this report of Davis tests. Susceptibility to mechanical damage and to splitting in the canned product continues to increase in beans cut after they have reached 50% moisture. Other advantages to earlier cutting include earlier marketing possibilities, more leaves to buffer seed damage during threshing, and higher quality beans.