Better Rice 73

Better Rice - 73
Project Leader and Principal Investigators M.D. Morse, California Cooperative Rice Research Foundation H.L. Carnahan C.W. Johnson S.T. Tseng D.E. Seaman, D.S. Mikkelsen, Integration and Improvement of Alternative Cultural and Crop Protection Practices for Rice Production (RM1) D.S. Mikkelsen, The Mineral Nutrition and Fertilization of Improved Plant Types (RB1) J.A. Hardy D.N. Rao M.L. Peterson, J.N. Rutger, Physiological and Genetic Determinants of Yield and Quality in Rice (RB3) D. Jones R.C. Buckman S.S. Lin L. Kramer C.C. Li S. Trees S. Khan K. Foster K. Taggard R.W. Breidenbach, Physiological and Genetic Determinants of Yield and Quality in Rice (RB5)	S6 PLANNED FOR 1975 DISTRIBUTION This pearl variety has Colusa maturity, 13% better yields and less lodging. Fifty acres of seed will be grown in 1974. (CCRRF) þ M5 NEARS RELEASE This medium-grain is similar to CS-M3 but 11 days earlier. Some 450 sacks will be available for field-scale testing and as a seed increase pending favorable results. (CCRRF) HIGHER YIELDS, LESS STRAW A short-statured experimental (70/6526) produced 14% more grain and 19% less straw than Colusa. Further, it did not lodge in most plots although Colusa lodged severely in all. (RM1) BETTER GRAIN TYPE SOUGHT IN SHORT-STATURES A large number of crosses in 1973 were aimed at improving the grain type in short-statured lines. (CCRRF) EARLY-MATURITY SUCCESSES In preliminary trials, 150 of 800 tall pearl and medium-grain lines yielded as well as Colusa and matured 10 days earlier. Three experimentals that mature very early outyielded Colusa at 4 locations. (CCRRF) SEEDLING VIGOR NEEDED IN SHORT-STATURES Especially important to short-statured varieties is seedling vigor because the shorter plants require shallow water for stand establishment. Selections for seedling vigor were made from 1,350 experimentals. (CCRRF) HIGH-PROTEIN HEADACHES Yields are so much lower in present high-protein lines that these are unsuitable for profitable production. Work continues in an attempt to overcome this. (CCRRF) FORECASTING SHORT-STATURE MANAGEMENT Proper fertilization and water management for short-statured varieties must be determined before they are released. Experiments are therefore probing the differences between the traditional tall types and the shorter ones as to growth patterns and changes in management practices thereby dictated. (RB1) SHORT-STATURE SENSITIVITY TO CHEMICALS A factor in screening varieties is the sensitivity to molinate and benthiocarb of the short-statured indica parents of new California rice varieties. Fortunately, that sensitivity isn't passed on to all offspring of crosses of indica with japonica. Also of concern to breeders is overcoming sensitivity to phenoxy types of herbicides. (RM1) Sensitivity to chemical damage differs with variety, and the differences seem heritable. Short-stature selections from indica x japonica crosses varied as much as their parents in susceptibility to molinate or MCPA-IPE. Making the susceptible indica germplasm less prominent by backcrosses with japonica might give greater resistance to molinate. It now appears that some selections discarded because of apparently poor seedling vigor in nursery fields may have been injured by molinate. Short-stature indica rice varieties, including I-Geo-Gen, I-Geo-Tze, Liu-Tao-Tze, Taichung 106, and Taichung N-1, proved susceptible to injury from molinate applied pre- or postflood, while most California (japonica) varieties were relatively resistant. Some, including IR8 and its parent DGWG, were more resistant to early applications of the isopropyl ester of MCPA (MCPA-IPE) than were standard California varieties. (RM1) GREATER YIELDS THROUGH BASICS Upping the potential yield of new rice varieties involves two breeding approaches: 1) breeding larger panicles with more and larger kernels; and 2) improving the efficiency of leaves in capturing solar energy and converting it to starch and protein in the grain. One stage of the second approach has been completed: the inheritance of leaf size and angle of display for maximum capture of sunlight. (RB3) Delving into the relation to growth of plant conversion efficiencies involves studies of gas-exchange characteristics such as photorespiration rate, photosynthetic efficiency, compensation point, and the pattern of specific leaf weight changes. Pinpointing such characteristics and determining the extent to which they are inherited is a part of a program that could benefit crops in general as well as rice. (RB5) ALTERNATIVE SHORT-STATURE SOURCES SOUGHT To anticipate possible future problems, alternate sources of short stature are being sought. The reason is that present varieties trace mostly to a single source. Potential sources of germplasm for further genetic and breeding work have been revealed by studies on the inheritance of short stature, combined with knowledge developed on breeding behavior in a cross with a California variety. (RB3)

Better Rice - 73

Project Leader and Principal Investigators

M.D. Morse, California Cooperative Rice Research Foundation

H.L. Carnahan

C.W. Johnson

S.T. Tseng

D.E. Seaman, D.S. Mikkelsen, Integration and Improvement of Alternative Cultural and Crop Protection Practices for Rice Production (RM1)

D.S. Mikkelsen, The Mineral Nutrition and Fertilization of Improved Plant Types (RB1)

J.A. Hardy

D.N. Rao

M.L. Peterson, J.N. Rutger, Physiological and Genetic Determinants of Yield and Quality in Rice (RB3)

D. Jones

R.C. Buckman

S.S. Lin

L. Kramer

C.C. Li

S. Trees

S. Khan

K. Foster

K. Taggard

R.W. Breidenbach, Physiological and Genetic Determinants of Yield and Quality in Rice (RB5)

S6 PLANNED FOR 1975 DISTRIBUTION

This pearl variety has Colusa maturity, 13% better yields and less lodging. Fifty acres of seed will be grown in 1974. (CCRRF)

þ M5 NEARS RELEASE

This medium-grain is similar to CS-M3 but 11 days earlier. Some 450 sacks will be available for field-scale testing and as a seed increase pending favorable results. (CCRRF)

HIGHER YIELDS, LESS STRAW

A short-statured experimental (70/6526) produced 14% more grain and 19% less straw than Colusa. Further, it did not lodge in most plots although Colusa lodged severely in all. (RM1)

BETTER GRAIN TYPE SOUGHT IN SHORT-STATURES

A large number of crosses in 1973 were aimed at improving the grain type in short-statured lines. (CCRRF)

EARLY-MATURITY SUCCESSES

In preliminary trials, 150 of 800 tall pearl and medium-grain lines yielded as well as Colusa and matured 10 days earlier. Three experimentals that mature very early outyielded Colusa at 4 locations. (CCRRF)

SEEDLING VIGOR NEEDED IN SHORT-STATURES

Especially important to short-statured varieties is seedling vigor because the shorter plants require shallow water for stand establishment. Selections for seedling vigor were made from 1,350 experimentals. (CCRRF)

HIGH-PROTEIN HEADACHES

Yields are so much lower in present high-protein lines that these are unsuitable for profitable production. Work continues in an attempt to overcome this. (CCRRF)

FORECASTING SHORT-STATURE MANAGEMENT

Proper fertilization and water management for short-statured varieties must be determined before they are released. Experiments are therefore probing the differences between the traditional tall types and the shorter ones as to growth patterns and changes in management practices thereby dictated. (RB1)

SHORT-STATURE SENSITIVITY TO CHEMICALS

A factor in screening varieties is the sensitivity to molinate and benthiocarb of the short-statured indica parents of new California rice varieties. Fortunately, that sensitivity isn't passed on to all offspring of crosses of indica with japonica. Also of concern to breeders is overcoming sensitivity to phenoxy types of herbicides. (RM1)

Sensitivity to chemical damage differs with variety, and the differences seem heritable. Short-stature selections from indica x japonica crosses varied as much as their parents in susceptibility to molinate or MCPA-IPE. Making the susceptible indica germplasm less prominent by backcrosses with japonica might give greater resistance to molinate. It now appears that some selections discarded because of apparently poor seedling vigor in nursery fields may have been injured by molinate.

Short-stature indica rice varieties, including I-Geo-Gen, I-Geo-Tze, Liu-Tao-Tze, Taichung 106, and Taichung N-1, proved susceptible to injury from molinate applied pre- or postflood, while most California (japonica) varieties were relatively resistant. Some, including IR8 and its parent DGWG, were more resistant to early applications of the isopropyl ester of MCPA (MCPA-IPE) than were standard California varieties. (RM1)

GREATER YIELDS THROUGH BASICS

Upping the potential yield of new rice varieties involves two breeding approaches: 1) breeding larger panicles with more and larger kernels; and 2) improving the efficiency of leaves in capturing solar energy and converting it to starch and protein in the grain. One stage of the second approach has been completed: the inheritance of leaf size and angle of display for maximum capture of sunlight. (RB3)

Delving into the relation to growth of plant conversion efficiencies involves studies of gas-exchange characteristics such as photorespiration rate, photosynthetic efficiency, compensation point, and the pattern of specific leaf weight changes. Pinpointing such characteristics and determining the extent to which they are inherited is a part of a program that could benefit crops in general as well as rice. (RB5)

ALTERNATIVE SHORT-STATURE SOURCES SOUGHT

To anticipate possible future problems, alternate sources of short stature are being sought. The reason is that present varieties trace mostly to a single source. Potential sources of germplasm for further genetic and breeding work have been revealed by studies on the inheritance of short stature, combined with knowledge developed on breeding behavior in a cross with a California variety. (RB3)