Genetic Gain in Yield Potential of Upland Cotton under Varying Plant Densities

Genetic gain studies have been used to evaluate the historical improvement of different traits, to provide insights into magnitudes of gain possible in future cultivars, and to defend the role of genetics during periods of stagnant or decreasing yield trends. This study was conducted over a 2-yr period and included nine current or obsolete cotton (Gossyplum hirsutum L.) cultivars grown in five plant densities to evaluate genetic gain with varying levels of interplant competition. The rates of genetic gain for lint yield were highest in the commercial, 1 by 0.3 m, and 1 by 1 m plant spacing treatments with slopes of 8.7, 8.2, and 7.1 kg ha -1 yr 1 , respectively. Slopes were reduced in the 2 by 2 m and 3 by 3 m spacing treatments with gains of 3.6 and 1.5 kg ha -1 yr 1 , respectively, implying that for lint yield, genetic gains have been made for tolerance to interplant competition and not only yield potential per se.

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