Relation of seed weight to grain yields in oats, Avena sativa L.
SummaryWe measured yielding ability and weight per 100 seeds in 7 populations of oat lines, each derived from a different cross. The association between these two traits was curvilinear, with maximum yields occurring when 100-seed weights were between 2.75 and 3.10 g.In a simulated selection experiment conducted on a bulk population of 150 oat lines (i.e. only lines with seed weight between 2.75 and 3.10 g per 100 seeds were saved), the proportion of superior yielding lines was increased from 16% in the original to 32% in the new one. In the 100-seed weight class below 2.75 g, the proportion of high yielding lines was only 5%.
Inheritance and Heritability of Seed Weight and Its Components in Oats 1
A COMMON objective of small grain breeding programs is to improve grain yield. With oats, as with other crops, grain yield variation is due to an interaction of environmental and genetic effects. One method proposed to circumvent this problem is to select for characteristics associated with or composing yield, i.e., yield components. Primary components of grain yield are number of panicles per plant, number of seeds per panicle, and weight per seed. It is conceivable that if heritability percentages for and correlations among yield components were used to construct an optimum selection index, the efficiency of selection might be greater than when yield performance was used. Since seed weight can be subjected to component analysis and measured relatively precisely with small sample size, this character was selected to study the theory and application of character component analysis.
The utility of hill plots in oat research
From 1955 through 1963, approximately 300,000 hill plots have been used in various experiments in the Iowa small grain research program. When grain yield, plant height, and heading date were measured on the same varieties, the genetic correlations between rod rows and hills were 0.98, 0.96 and 0.96, respectively.The coefficients of variation for plant height, weight per volume, spikelets per panicle, panicles per plant, weight per 100 seeds were similar for rod rows and hills. However, the coefficients of variability for grain yield ranged from 2 to 5 times larger for hills than for rod rows. Competition between varieties in adjacent hills had little effect on the performance of varieties.The best method for planting hill plots is the conventional method opening a hole in the soil about 2 inches deep with a hoe, pouring the seed in the hole, and covering it with soil. Rates of planting influenced the expression of grain yield, panicles per plant, and spikelets per panicle, but not weight per 100 seeds and plant height. Approximately 30 seeds per hill appeared the most desirable planting rate.