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Growth Form and Yield Responses of Four Cotton Cultivars to Ozone
Author(s) -
Temple Patrick J.
Publication year - 1990
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1990.00021962008200060003x
Subject(s) - cultivar , biology , agronomy , abscission , fiber crop , malvaceae , yield (engineering) , loam , horticulture , gossypium hirsutum , ecology , soil water , materials science , metallurgy
Cultivars of crop plants can differ widely in their susceptibilities to yield losses induced by the air pollutant ozone (O 3 ), but relatively little is known of the physiological mechanisms that account for these differences. Cotton ( Gossypium hirsutum L.) cultivars differ in degree of determinance, which may affect cultivar responses to O 3 through effects on rates of maturation of the cultivars. Four cultivars of cotton grown in the field on a Hanford coarse sandy loam (coarseloamy, mixed, nonacid, Thermic Xerorthents) were exposed to three levels of O 3 in open‐top chambers to determine their relative susceptibility to O 3 , and to relate differences in susceptibility to morphological and physiological characteristics of the cultivars. Susceptibility to O 3 ,‐induced yield losses in these cultivars was directly correlated with degree of determinance so that cultivar rank in order of both increasing determinance and susceptibility to O 3 was: SJ‐2 < C1 < GC510 < SS2086. Differences among the cultivars in susceptibility to O 3 , were not associated with differences in rates of stomatal conductance. Instead, determinate cultivars appeared to be more susceptible to O 3 because periods of peak flowering and boll set coincided with periods of high O 3 concentration. Also, indeterminate cultivars appeared to have greater flexibility in altering branching patterns in response to O 3 ,‐induced leaf abscission than did determinate lines. Since most high‐yielding, short‐season cotton cultivars have a determinate growth habit, these results suggest that production from short‐season cotton cultivars may be limited by the prevalence of O 3 air pollution in many cotton‐growing regions of the USA.