2001 Table of Contents

2001 STEEP III Progress Report

TITLE: Developing agronomic practices for direct drilling winter canola into cereal stubble.

INVESTIGATORS:
Jack Brown, Plant Breeder, University of Idaho, Moscow, Idaho
Don Wysocki, Extension Soil Scientist, Oregon State Univ. CBARC, Pendleton, Oregon
Brown coordinates trails in Idaho and Wysocki coordinates trials in Oregon.
Other Team members that have cooperated on this project are Bill Payne, Research Agronomist CBARC, Pendleton, Oregon and Dale Wilkins, Agricultural Engineer and Research Leader, ARS Pendleton.

INTERIM REPORT: Year two of project started fall of 1999

RESEARCH OBJECTIVE:

• Screen advanced breeding material with late-planting ability under direct-seeding conditions.

KEY WORDS: winter canola, direct seeding, crop management.

STATEMENT OF PROBLEM: Agronomic practices for winter Canola have been developed for planting on summer fallow. These practices have focused on stand establishment in late August to mid September. This planting option is not possible when planting Canola immediately after a cereal crop. The seedbed usually is too dry at this time. New agronomic recommendations are needed to successfully seed winter Canola into cereal residues. In addition it is essential to examine whether cultivars developed for conventional management systems (tilled summer fallow) are the most adapted cultivars when direct seeded.

AGRONOMIC ZONE OF INTEREST: This research will apply to all agronomic zones where recropping of winter Canola is feasible. We expect that it will be most applicable in agronomic zones 1, 2, 3, and 4.

ABSTRACT OF RESEARCH RESULTS

Eighty winter canola genotypes, a combination of commercial cultivars and advanced University of Idaho breeding selections, were planted under conventional management (full tillage summer fallow) and direct seeded into standing cereal straw. Yield potential under the two systems was examined along with the relative performance of individual lines. Relative performance of genotypes differed markedly under the two systems. The 'best' lines under direct seeding were ones that had been specifically selected to have late planting potential. Overall, it is obvious that breeding lines must be evaluated under conventional and direct seeding management practices to ensure that cultivars can be released that have greatest yield potential under the different systems.

RESULTS AND INTERPRETATIONS

Screen breeding lines

Two sets of winter canola cultivars were evaluated: (1) entries in the Pacific Northwest Winter Canola Trial (PNWWCT); and (2) fifty three advanced breeding lines from the University of Idaho breeding program along with 7 named control cultivars. These lines were planted at four locations in the fall of 2000 (Moscow, Genesee, Lewiston and Pendleton). Late fall rains delayed planting the no tillage plots and the Lewiston and Moscow sites were lost dues to poor plant establishment. Although the no tilled plants were very small (2-3 leaf stage) the mild winter caused little winterkill and all plots were well established in the spring of 2001. As with the previous years trials (see 2000 report), greatest difficulties were encountered in the direct seeding in straw management, which resulted in poor seed-soil contact and uneven germination and stand. In addition, poor stand in late plated direct seed plots resulted in greater weediness and competition from weeds must have added to reduced yields.

Yield of all entries tested were significantly reduced when direct seeded compared to conventionally managed systems. Under conventional management average seed yield in the PNWWCT was 2505 lb/acre, while under direct seeding the average was only 1867, which was a 25% reduction in yield. The average yield of the breeding lines under conventional tillage was significantly higher at 4141 lb/acre while the average yield under direct seeding was less than half this (1932 lb/acre). When the cultivars entered into the PNWWCT were examined over conventional and direct seeding, it was found that the relative ranking showed that there was a negative relationship between performance between direct seeding and conventional tillage (r = -0.19), (Figure 1). Highest yield from conventional tillage was from 'Olsen' (3612 lb/acre), but this cultivar ranked lowest yield under direct seeding. The second highest yielding cultivar when conventionally tilled was 'Athena', which also did comparatively well when direct seeded (2564 lb/acre). The highest yielding entry in the PNWWCT under direct seeding was the advanced University of Idaho breeding line '92.WC.3.134212' (3020 lb/acre). It is perhaps interesting to note that this line was the result of conscious selection in Idaho and Oregon for late-planting potential. Indeed this was one of the few PNWWCT entries with higher yield under direct seeding.

The relationship between performance in tilled and no tilled advanced breeding lines trials was positive (r = 0.25) but relatively small, accounting for slightly more than 6% of the total variation in yield between the tillage treatments. This correlation was almost the same as that found in the previous year study (r = 0.26). Despite the positive correlation for yield, from a practical breeding prospective the relationship was poor (Figure 2). For example, the highest yielding lines in the conventional seeding trial (5934 lb/acre) was ranked as 13th when direct seeded. Similarly, if the top 10 yielding cultivars was selected based only on their performance under conventional management, then only 2 of these would have been amongst the top 10 yielding lines under direct seeding (Table 1). Similarly, the highest yielding line when direct seeded (2864 lb/acre) ranked as only 39th when conventionally seeded.

Overall, it is obvious that breeding lines must be evaluated under conventional and direct seeding management practices to ensure that cultivars can be released that have greatest yield potential under the different systems.

INTERACTION WITH OTHER SCIENTISTS CONDUCTION RELATED ACTIVITY

This project is complimentary to other cropping system projects currently funded by STEEP. There is communication and interaction with Stephen Guy, Dan Ball, and Bill Schillinger. In addition, the PI's on this project are in constant communication

Table 1. Relative ranking of advanced breeding lines for yield (1 = highest yield) when grown under conventional tillage (Tilled) and when direct seeded into straw stubble (No-Tilled)

Figure 1. Yield of Pacific Northwest Winter Canola Trial entries when direct seeded and when conventionally seeded.

Figure 2. Yield of advanced breeding lines when direct seeded and when conventionally seeded.

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