Heritability of plant architecture in diploid roses
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2019 International Society for Horticultural Science. All Rights Reserved. Plant architecture, which is the result of both the plant organization and the interaction between the plant and the environment, affects the ornamental value and flower productivity of roses. Thus, it is helpful to understand the genetic basis of plant architecture so that breeding efforts can be directed towards improved architecture. To this end, six architectural traits (plant height, number and length of primary shoots, number of nodes on primary shoot, number of secondary and tertiary shoots per primary shoot) were evaluated in May and December of 2015 in College Station, TX, for 13 interrelated diploid rose populations segregating for plant architecture types. Three of the traits (number of primary shoots, length of primary shoots, and number of nodes on primary shoot) exhibited low to moderate narrow sense heritability but moderately high to high broad sense heritability, indicating an important non-additive genetic component. The number of nodes on the primary shoots and the number of secondary and tertiary shoots per primary shoot displayed a large genotype by environment interaction. A comparison of desirable and undesirable plant growth types indicated that desirable growth types have more than 30 primary shoots with multiple secondary/tertiary shoots. The 13 rose populations have been genotyped for single nucleotide polymorphisms (SNPs) and the next step will be to perform a quantitative trait loci (QTL) analysis using FlexQTL to identify markers for high numbers of primary shoots.