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Several laboratory tests currently exist for the evaluation of seed quality (viability and vigor). These tests may broadly be classified into the following categories: 1.) seedling growth and evaluation tests, 2.) stress tests, and 3.) biochemical tests. The purpose of this study (conducted during 1981 and 1982) was to evaluate several of these tests as to their ability to predict actual field performance. Six widely grown High Plains cotton cultivars were chosen for evaluation. Seed of the cultivars were subjected to the following laboratory tests: 1.) warm germination test (WGT), 2.) cool germination test (CGT), 3.) electrical conductivity test (EC), 4.) accelerated aging test (AA). 5.) protein content, 6.) oil content and 7.) free fatty acid content. In addition, seed of these cultivars were planted in the field on two dates and at two depths in order to create a range of stressful conditions to emergence during both years. Unfortunately the first planting date materials during 1982 were lost due to a hail storm. Field evaluation of the cultivars included the following: 1.) emergence rate index (ERI) - a measure of the rate and totality of germination/emergence, 2.) establishment index corrected (EIC-6) - a measure of the percent of viable seeds planted that produced surviving plants six weeks after planting. 3.) Pry matter production six weeks after planting (DM-6), 4.) leaf area index six weeks after planting (LAI-6), 5.)lint yield. 6.) seed yield and 7.) percent turnout. During 1981, the warm germination test (WGT) correlated well with the ERI (r=0.94**), EIC-6 (r=0.89*), DM-6 (r=0.95**), LAI-6 (r=0.94**), and the lint yield (r=0.81*). The cool germination test (CGT) also was correlated with the ERI (r=0.91*), EIC-6 (r=0.84*), DM-6 (r=0.90*), and the LAI-6 (r=0.86*). The only other test indicating any statistical significance was a correlation of the oil content with EIC-6 (r=0.80*). During 1982 few tests indicated statistical significance. The WGT, CGT, and AA all correlated with the ERI with correlation coefficients of r=0.90*, r=0.97**, and r=0.91*, respectively. Other tests that approached significance at the 5% level were: 1.) EC with ERI, r=-O.80; 2.) oil with ERI, r=0.83; 3.)WGT with EIC-6. r=0.83; and 4.) oil with EIC-6, r=0.83. In summary, these data would indicate, to varying degrees, that the WGT, CGT, AA, and oil content correlated with the emergence and early season growth of cotton under the conditions of this study. Very little correlation was noted between the lab test and the yield parameters. However, this is not unexpected given the number of environmental factors "operating" between stand establishment and maturity. |
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©National Cotton Council, Memphis TN |
Document last modified Sunday, Dec 6 1998
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