Relationship of Test Weight and Kernel Properties to Milling and Baking Quality in Soft Red Winter Wheat

Abstract

Although test weight is used as a grading criterion and an indication of quality in wheat (Triticum aestivum L.), its relationship to specific quality parameters in soft wheat is not well documented. Seed characteristics, flour yield, and baking quality were studied in 24 soft red winter wheat (SRWW) genotypes grown in six environments to determine their relationship to test weight. Flour yield, flour protein, alkaline water retention capacity (AWRC), and softness equivalent (SEQ) were evaluated by the micro-procedures of the USDA-ARS soft wheat carly-generation milling and baking quality evaluation program. Despite removal of shriveled kernels prior to evaluation, environmental effects had a significant impact on quality parameters, ranging from 68% of total variability (SEQ) to 5% (AWRC). Test weight was correlated with flour yield, but was significantly correlated with flour protein content (r = 0.54, P < 0.05) as was kernel density (r = 0.49). Thousand-kernel weight, diversity of seed size, proportion of large seed, and average kernel length and width were not correlated with flour yield or other quality parameters. Test weight did not predict flour yield in SRWW when shriveling was absent, but it was related to flour protein content, which is associated with baking quality. Kernel size or size distribution did not affect end-use quality. The best predictive model based on the characters above explained little of the total variation in flour yield (R 2 = 0.22). S OFT WHEAT BREEDERS must consider milling and baking quality in cultivar improvement. Criteria of good baking quality of soft wheat flour may differ according to intended end-product use (Bass, 1990). Milling quality describes traits important in the milling process such as kernel texture and flour yield. Flour yield is expressed as the percent of flour obtained from a given amount of

KERNEL MORPHOLOGY VARIATION IN A POPULATION DERIVED FROM A SOFT BY HARD WHEAT CROSS AND ASSOCIATIONS WITH END‐USE QUALITY TRAITS1

“…Similar results have been reported for TW and TKW in soft red winter wheat grown in multiple locations (Schuler et al 1995). Therefore, the effect of environment on TW from causes other than shriveling can be substantial.…”

“…But PRO and TKW were not associated, thus suggesting that some component besides PRO, which also influences kernel density, created the association between DF and TKW. Others have reported similar phenotypic correlations between kernel density and PRO, but not between kernel density and TKW (Yamazaki and Briggle 1969;Schuler et al 1995).…”

“…Test weight (TW) has been reported by some to be a good predictor of FY, while others have documented that measurement may not be reliable for soft or hard wheat predictions Hook 1984;Finney and Bergman 1994;Schuler et al 1995). Since no other practical method has been found to supplement or replace TW in the wheat current grading system, it continues to be studied and wheat breeders continue to have a focus on producing genotypes with high TW.…”

Physical characteristics of Brazilian wheat and their utilization as an indication of flour extraction

“…Schuler et al (1995) and Johnson & Harris (1995) did not find a significant correlation between FE and TW or TKW. To verify if the relations between FE and TW were influenced by the apparent kernel density, the coefficient of determination between these two parameters in several TW ranges was calculated as shown in Table 4.…”

“…Although this parameter reflects very reasonably the grain sanity and its degree of development, it is also used as an indicator of the milling flour extraction (FE). Kremer (1993) found a high correlation between TW and FE while Johnson & Harris (1995) and Schuler et al (1995) did not find a significant correlation coefficient. Other parameters used as flour yield indicators are thousand kernel weight (TKW) (El-Shirbeeny & Allam, 1987) and kernel hardness (Baker & Dick, 1975).…”