Heritability and genetic variance components for 20 fruit and plant characters were investigated in 64 progenies produced among 31 North American and 1 German strawberry clone under the crossing scheme similar to North Carolina Design II (Comstock and Robinson, 1952). The data were analyzed based on the assumption of random and/or mixed models of the parents. The estimation of the genetic variance components indicated that for more than half the 20 characters nonadditive variance (dominance + epistasis) constituted approximately 50% or more of the total genetic variance and that in most cases epistasis played an important role in the nonadditive variance. Heritability estimates were low (less than 18%) for total berry yield and some fruit quality characters such as firmness, easy capping, pH value, soluble solids, and external and internal appearances but were high (more than 37%) for a number of yield component characters such as average berry weight, berries/flower stalk, yield/flower stalk and flower stalk number, suggesting that substantial improvement in total berry yield could be achieved through selection on these yield components or a linear function of them.

The performance in fruit yield characteristics and fruit appearance of seven Premier S5 inbred selections was studied in their crosses with four tester varieties, Redcoat, Senga Sengana, Sparkle and Jerseybelle. Some of the progenies produced by crossing Premier S5, inbreds with testers were superior in a number of yield characters to those produced when Premier was crossed to the same testers. This suggests that inbreeding, although expensive and time consuming, may be a useful step in one type of approach to breeding for higher yield in the cultivated strawberry.General combining abilities of the inbred selections and of the testers were both significant for all but one character, while specific combining ability of inbreds × testers was significant for six of the eight characters. The estimates of general combining ability effects of the inbreds and the testers were found to be of limited value in predicting the most desirable single crosses. The significance of this is discussed together with a proposed procedure for exploiting inbreeding in strawberry breeding.

The inheritance of flour protein content and sedimentation value was investigated in diallel crosses among four hard red spring wheat varieties. Variances for the space-planted parental and F2 populations were relatively high. Broad sense heritability values for each trait averaged 55% in the six crosses. Use of purified lines as parents in a 3-selection diallel did not alter the heritability of protein content but the estimates for sedimentation value were substantially improved.Phenotypic correlations in the F2 populations indicated the two quality traits had no consistent relationship, positive or negative depending on the cross. The negative association of protein content with grain yield was significant in nearly all crosses.The diallel cross analysis showed that each quality factor was controlled primarily by intragenic allele systems. Sedimentation value showed partial dominance, with dominant genes contributing to high measurement. Over-dominance in slight magnitude was indicated for protein content, with both dominant and recessive genes contributing to the high expression of this character.

General.a,nd specific combining abilities were density. General and specific combining abiliana-lyzed. for to_tal, marketable, early, and late ties for the five characlers were highly signiyield, and for flower stalk number in a diallel ficant. Estimates of general combining ability cross of eight strawberry cultivars. Data were effects taken alone i'ere, in general, of tittt?t recorded from individual seedlings restricted value in predicting the ordei of desirability to two runner plants, thereby eliminating of individual crosses.variability resulting from differences in plant

Genetic, p!motypic and environmental correlations and coheritabilides berween ZR fru~t and plant characters were estimated in 64 progenia produced among 31. North American strawberry clones and 1 German one under the crossing scheme similar to North Carafina Desip 11. Total berry and total marketable yields were positively and significantly correlated with average berry weighr, hrries per flower stalk, yield per flower stalk, leaf area, and petiole diameter, but negativcly correlated wirh stolon number and flower stalk number. The invcrsc relationsIlips bctween flower stdk number with average berry weighr, and with berries pcr flower stalk may be genetically dependent or arise from dmIoprnentally induced relacionships. Plant height appeared to be a goad indicator of both early and early marketable yields; petiole number tvas considcrcd the bcsr indicaror of solubIe solids and easy capping, while soluble solids may be of value as an indicator of both late and late marketable yields. In general, no genetic barrier was detected to combine high yield with good quality of the berry.