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Effect of Divergent Selection for Root Weight on Genetic Variation for Root and Shoot Characters in Alfalfa 1
Author(s) -
Pederson G. A.,
Kendall W. A.,
Hill R. R.
Publication year - 1984
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1984.0011183x002400030033x
Subject(s) - diallel cross , biology , shoot , cultivar , dry weight , horticulture , dry matter , agronomy , hybrid
Thirty plants each from two hardy (‘Grimm’ and ‘Teton’), two moderately hardy (‘Saranac’ and ‘Lahontan’), and from two nonhardy (‘Moapa’ and ‘Mesa Sirsa’) alfalfa ( Medicago sativa L.) cultivars were grown in a simulated growing season environment in plant growth chambers. Shoots and roots were harvested five times during this simulated growing season. From each cultivar, one plant with an accumulated fresh root weight consistently greater and one plant with an accumulated fresh root weight consistently less than the cultivar mean were selected and crossed in a 12 × 12 diallel. Diallel progenies were evaluated in two greenhouse trials to determine the effects of selection for high and low root weight on the expression of related vigor traits in the progenies of the selected parents. Progenies from high‐rootweight (HRW) selections had greater root diameters, root branching, and shoot weights than did progenies from low‐rootweight (LRW) selections in both greenhouse trials. Root weight and shoot number were greater in progenies from high than from low‐root‐weight selections in the greenhouse trial conducted in the spring. Differences between progenies of high and low‐root‐weight parents tended to be greater for parents from Mesa Sirsa and Moapa than for parents from the other cultivars. Progenies from HRW selections had greater root diameter, root dry weight, and shoot dry weight when the parent was used as a female than when it was used as a male. The opposite trend was observed for progenies of LRW selections—means were greater when the parent was used as a male than when used as a female. Maternal effects for root diameter, root weight, and shoot weight were expressed with greater intensity in plants evaluated in the spring than in those evaluated in the fall. The presence of maternal effects for certain root characteristics in alfalfa could complicate selection for root traits.