Analysis of heterosis of upland cotton lines with natural color fiber.

To analyze heterosis and combining ability,the green crosses were made between 3 white fiber lines and 3 green fiber lines by NCⅡ design,the brown crosses were made between 2 white fiber lines and 4 brown fiber lines by NCⅡ design too.The results showed that,for green fiber,the AH-heterosis over white fiber parent,the MH-heterosis over MH-parent value,the PNH-heterosis over color fiber parent and the CH-heterosis over check of 2.5 % span length were 0.91 %,6.53 %,13.02 % and 1.21 %.The AH,MH,PNH and CH of fiber strength were -5.77 %,15.63 %,49.7 % and 1.02 %.The AH,MH,PNH and CH of micronaire were 14.6 %,9.31 %,52.51 % and-23.61 %.For brown fiber,The AH,MH,PNH and CH of 2.5 % span length were-3.09 %,1.71 %,7.12 % and-5.59 %.The AH,MH,PNH and CH of fiber strength were -6.99 %,-0.06 %,9.55 % and-4.05 %.The AH,MH,PNH and CH of micronaire were-8.67 %,-3.15 %,4.49 % and-18.37 %.For green fiber,the GCA and SCA variance ratio to phenotype were significant and were 56.18 % and 31.32 %,The SCA variance ratio to phenotype of fiber strength was 59.53 % and the SCA variance ratio to phenotype of micronaire was significant and was 39.22 %.For brown fiber,the GCA variance ratio to phenotype of 2.5 % span length was 68.59 %,the GCA variance ratio to phenotype of fiber strength was significant and was 37.77 %,the GCA and SCA variance ratio to phenotype of micronaire value were significant and were 54.75 %and 34.69 %.