Variety Trials 02

Variety Trials - 02
Project Leader and Principal UC Investigators Randall “Cass” Mutters, UC farm advisor, UC Cooperative Extension, Butte County	Sixteen on-farm rice variety evaluation trials were conducted throughout the rice growing regions of California in 2002 by University of California farm advisors in cooperation with public and private plant breeders. These trials perform an essential role in the development of new varieties by exposing standard, advanced and preliminary varieties to a range of environments, cultural practices and disease levels. Six similar tests were conducted at the Rice Experiment Station in Biggs. Average yields across varieties and locations ranged from about 7,960 pounds/acre in the very early trials to 10,830 pounds/acre in the intermediate tests. The combination of a dry, warm planting season and midseason temperatures produced a favorable climate for rice in most areas. Very little blanking was observed in the statewide trials. Two trials became heavily infested with weeds and required a hand rouging to ensure the integrity of the experiments. As in previous years, the commercial standards ranked high in yield against the advanced and preliminary entries, demonstrating that yield advances are difficult to attain. However, a few advanced lines produced very high yields and exhibited good plant characteristics. Testing advanced and preliminary lines under a variety of conditions remains a critical aspect of releasing varieties adapted to changing cultural practices, markets and pests. Three rice variety strip trials were conducted to evaluate the potential new medium grain cultivar, 98-Y-242 across different environments. 98-Y-242 yields were comparable to the standard varieties at all locations. This project also examines cultural practices associated with existing and upcoming varieties. One study looked at optimal preplant nitrogen levels for three new varieties, one advanced line and two standards (M-205, M-402, M-104, 98-Y-242, S-102 and M-202). Optimum nitrogen ranged from 140 to 150 pounds/acre. Another study examined whether a link exists between seeding rates and nitrogen levels. Finally, a new moisture meter on the UC plot combine is proving a very accurate method of field-level grain moisture measurements. Read below for more details on this research and results from 2002 variety trails. Very Early Tests Ten advanced breeding lines and eight commercial varieties were compared in four very early advanced tests (less than 90 days to 50 percent heading). Additionally, 32 cultivar lines were tested in the preliminary trials at each location. Grain yield in the advanced tests averaged 10,040 pounds/acre at RES, 8,510 pounds/acre at San Joaquin, 9,170 pounds/acre at Sutter and 8,540 pounds/acre at Yolo. Over the four locations, the highest yielding entry on average M-104 at 9,690 pounds/acre, followed closely by the advanced medium line 98-Y-242 at 9,660 pounds/acre, S-102 at 9,650 pounds/acre and medium-grain line 00-Y-228 at 9,600 pounds/acre. Other top-yielding commercial varieties included M-202, M-103 and L-205. Time to maturity was similar to 2001. For instance, S-102 reached 50 percent heading in 80 days both years. Overall average was 85 days in both 2001 and 2002. Only L-204 exhibited no lodging at all locations. Early Tests Eleven advanced lines and 10 commercial varieties were compared in four early tests (90-97 days to 50 percent heading). Another 30 preliminary lines were also evaluated in separate tests at each location. Yields in the advanced-line tests averaged 9,790 pounds/acre at RES, 8,450 pounds/acre at Butte, 8,410 pounds/acre at Colusa and 8,310 pounds/acre at Yuba. The medium grain M-205 was again the highest yielding entry at 9,550 pounds/acre averaged over the four locations in 2002. Other high-yielding entries were 98-Y-242, 98-Y-529 and S-102, although only 98-Y-242 ranked in the top 10 at all locations. M-205 was the highest yielding commercial variety at 8,882 pounds/acre, followed by 8,726 pounds/acre (averaged over the last five years). Time to 50 percent heading ranged from 82 days at Butte to 97 days at the Colusa site. Intermediate to Late Test Eight advanced lines and six commercial varieties were compared in three intermediate-late tests (more than 97 days to 50 percent heading). Twenty preliminary lines were also evaluated in separate tests at each location. Average yields in the advanced-line tests were 10,830 pounds/acre at RES, 8,180 pounds/acre at Glenn and 8,840 pounds/acre at Sutter — up from 2001. M-205 was the highest yielding entry overall at any location — 11,600 pounds/acre. Advanced long grain 94-Y-663 was the highest yielding line at 12,870 pounds/acre. Time to maturity ranged from 87 days at RES to 96 days at Glenn. M-402 took the longest to head among commercial varieties — 108 days at Glenn. Averaged over the last five years, M-205 was the highest yielding commercial variety at 9,521 pounds/acre. M-402 produced 8769 pounds/acre on average the last five years, representing a 1.5 percent increase over M-202. Variety-Nitrogen trial Two trials were established in commercial rice fields in Sutter and Butte counties, comparing six varieties at five preplant nitrogen rates in small plots. The trial was rolled, flooded, then hand seeded. Optimal yields for all varieties — M-205, M-402, M-104, 98-Y-242, S-102 and M-202 — as determined in this trial were at rates between 140 and 150 pounds N/acre. Some growers are realizing a yield increase with split applications, but the potential benefit of this practice, particularly within the context of new straw management practices and new varieties, requires further study. M-205 seeding rate Observations from the 2001 season indicated that dense plant populations, especially under high nitrogen levels, might compromise yields of M-205. A seeding rate by nitrogen level study was conducted to test this observation under controlled conditions. Plots with seeding rates of 100, 150 and 200 pounds/acre were treated with N rates of 0, 50, 100, 150 and 200 pounds/acre. No consistent trends in yield response to seeding rates in relation to nitrogen rates were observed. Moisture meter calibration Accurate grain moisture measurement is a vital component of germplasm evaluation. The range of maturity among varieties in a trial results in a broad range of harvest moistures. Thus, reliable measurements of moisture content over a range of values are essential for comparing performance across locations. The UC plot combine was equiped with a new moisture meter. To ensure moisture meter calibration accurately reflected California rice varieties, a rigorous effort was undertaken to establish calibration curves relating meter output. Regression analysis established a high level of accuracy for all grain types.

Variety Trials - 02

Project Leader and Principal UC Investigators

Randall “Cass” Mutters, UC farm advisor, UC Cooperative Extension, Butte County

Sixteen on-farm rice variety evaluation trials were conducted throughout the rice growing regions of California in 2002 by University of California farm advisors in cooperation with public and private plant breeders. These trials perform an essential role in the development of new varieties by exposing standard, advanced and preliminary varieties to a range of environments, cultural practices and disease levels.

Six similar tests were conducted at the Rice Experiment Station in Biggs. Average yields across varieties and locations ranged from about 7,960 pounds/acre in the very early trials to 10,830 pounds/acre in the intermediate tests. The combination of a dry, warm planting season and midseason temperatures produced a favorable climate for rice in most areas. Very little blanking was observed in the statewide trials. Two trials became heavily infested with weeds and required a hand rouging to ensure the integrity of the experiments.

As in previous years, the commercial standards ranked high in yield against the advanced and preliminary entries, demonstrating that yield advances are difficult to attain. However, a few advanced lines produced very high yields and exhibited good plant characteristics. Testing advanced and preliminary lines under a variety of conditions remains a critical aspect of releasing varieties adapted to changing cultural practices, markets and pests. Three rice variety strip trials were conducted to evaluate the potential new medium grain cultivar, 98-Y-242 across different environments. 98-Y-242 yields were comparable to the standard varieties at all locations.

This project also examines cultural practices associated with existing and upcoming varieties. One study looked at optimal preplant nitrogen levels for three new varieties, one advanced line and two standards (M-205, M-402, M-104, 98-Y-242, S-102 and M-202). Optimum nitrogen ranged from 140 to 150 pounds/acre. Another study examined whether a link exists between seeding rates and nitrogen levels. Finally, a new moisture meter on the UC plot combine is proving a very accurate method of field-level grain moisture measurements. Read below for more details on this research and results from 2002 variety trails.

Very Early Tests

Ten advanced breeding lines and eight commercial varieties were compared in four very early advanced tests (less than 90 days to 50 percent heading). Additionally, 32 cultivar lines were tested in the preliminary trials at each location.

Grain yield in the advanced tests averaged 10,040 pounds/acre at RES, 8,510 pounds/acre at San Joaquin, 9,170 pounds/acre at Sutter and 8,540 pounds/acre at Yolo. Over the four locations, the highest yielding entry on average M-104 at 9,690 pounds/acre, followed closely by the advanced medium line 98-Y-242 at 9,660 pounds/acre, S-102 at 9,650 pounds/acre and medium-grain line 00-Y-228 at 9,600 pounds/acre. Other top-yielding commercial varieties included M-202, M-103 and L-205.

Time to maturity was similar to 2001. For instance, S-102 reached 50 percent heading in 80 days both years. Overall average was 85 days in both 2001 and 2002. Only L-204 exhibited no lodging at all locations.

Early Tests

Eleven advanced lines and 10 commercial varieties were compared in four early tests (90-97 days to 50 percent heading). Another 30 preliminary lines were also evaluated in separate tests at each location.

Yields in the advanced-line tests averaged 9,790 pounds/acre at RES, 8,450 pounds/acre at Butte, 8,410 pounds/acre at Colusa and 8,310 pounds/acre at Yuba. The medium grain M-205 was again the highest yielding entry at 9,550 pounds/acre averaged over the four locations in 2002. Other high-yielding entries were 98-Y-242, 98-Y-529 and S-102, although only 98-Y-242 ranked in the top 10 at all locations. M-205 was the highest yielding commercial variety at 8,882 pounds/acre, followed by 8,726 pounds/acre (averaged over the last five years). Time to 50 percent heading ranged from 82 days at Butte to 97 days at the Colusa site.

Intermediate to Late Test

Eight advanced lines and six commercial varieties were compared in three intermediate-late tests (more than 97 days to 50 percent heading). Twenty preliminary lines were also evaluated in separate tests at each location.

Average yields in the advanced-line tests were 10,830 pounds/acre at RES, 8,180 pounds/acre at Glenn and 8,840 pounds/acre at Sutter — up from 2001. M-205 was the highest yielding entry overall at any location — 11,600 pounds/acre. Advanced long grain 94-Y-663 was the highest yielding line at 12,870 pounds/acre.

Time to maturity ranged from 87 days at RES to 96 days at Glenn. M-402 took the longest to head among commercial varieties — 108 days at Glenn. Averaged over the last five years, M-205 was the highest yielding commercial variety at 9,521 pounds/acre. M-402 produced 8769 pounds/acre on average the last five years, representing a 1.5 percent increase over M-202.

Variety-Nitrogen trial

Two trials were established in commercial rice fields in Sutter and Butte counties, comparing six varieties at five preplant nitrogen rates in small plots. The trial was rolled, flooded, then hand seeded. Optimal yields for all varieties — M-205, M-402, M-104, 98-Y-242, S-102 and M-202 — as determined in this trial were at rates between 140 and 150 pounds N/acre.

Some growers are realizing a yield increase with split applications, but the potential benefit of this practice, particularly within the context of new straw management practices and new varieties, requires further study.

M-205 seeding rate

Observations from the 2001 season indicated that dense plant populations, especially under high nitrogen levels, might compromise yields of M-205. A seeding rate by nitrogen level study was conducted to test this observation under controlled conditions. Plots with seeding rates of 100, 150 and 200 pounds/acre were treated with N rates of 0, 50, 100, 150 and 200 pounds/acre. No consistent trends in yield response to seeding rates in relation to nitrogen rates were observed.

Moisture meter calibration

Accurate grain moisture measurement is a vital component of germplasm evaluation. The range of maturity among varieties in a trial results in a broad range of harvest moistures. Thus, reliable measurements of moisture content over a range of values are essential for comparing performance across locations.

The UC plot combine was equiped with a new moisture meter. To ensure moisture meter calibration accurately reflected California rice varieties, a rigorous effort was undertaken to establish calibration curves relating meter output. Regression analysis established a high level of accuracy for all grain types.