Abstract: In this investigation, four different varieties and pigment-glandless as a marker were used to study the changes of the plant traits of upland cotton under genotypic competition. The results indicated that the productivity of the genotype,which had the highest yield when planted as a single line,decreased under the genotypic competition in varietal mixture. The yield capacity,however,of the genotype,which yielded lower as single-line planting,increased under such acompetition. The higher yield a variety had,the lower the expected yield of the varietal blends consisted of the variety was. Each mixture yielded lower than the component which had the highest yield lower as a single-line. Also,the yield of most blends was lower than the means of its componts. The apparent competition effects on seed cotton yield,lint yield and the number of boll per pant were detected. Nevertheless,no apparent competition effect was found in boll weight and lint percentage.

Key words: Uplan cotton, Genotype, Competition Yield, Yield components

CLC Number: 

• S562