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Yield Components, Plant Morphology, and Forage Quality of Alfalfa as Influenced by Plant Population 1
Author(s) -
Volenec J. J.,
Cherney J. H.,
Johnson K. D.
Publication year - 1987
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/cropsci1987.0011183x002700020040x
Subject(s) - biology , shoot , population , forage , yield (engineering) , agronomy , horticulture , plant morphology , botany , materials science , demography , sociology , metallurgy
Understanding differences in herbage yield of alfalfa ( Medicago sativa L.) can be simplified by using yield components: plants per area; shoots per plant; and yield per shoot (YPS). Our objective was to examine the influence of plant population on yield components, plant morphology, and forage quality of ‘Vernal’, ‘Hi‐Phy’, and Beltsville International Composite 5‐WH alfalfa. Ten‐week‐old seedlings were transplanted in 0.9‐m 2 plots at populations of 11, 22, 43,97, and 172 plants m −2 in early May 1984 and 1985. Plants were clipped in late June of both years, and plants were harvested at first flower, twice in 1984, and three times in 1985. Yield per area increased with plant population up to 172 plants m −2 , while yield per plant, shoots per plant, and YPS decreased with increasing plant populations. Path coefficient analysis indicated that YPS was always an important component of yield per plant, but especially so at high plant populations. Stem diameter and nodes per stem decreased as plant population increased. Stems from plants grown at 172 plant m −2 populations contained 10 g kg −1 less lignin and were 30 g kg −1 more digestible than were stems from plants grown at 11 plant m −2 populations. Vernal produced more and finer stems per plant, and these stems were lower in lignin and higher in digestibility when compared to the other cultivars. Selection of genotypes with high YPS may be an effective means of increasing yield, but may result in larger diameter, less digestible stems.