Two New Gossypium Species from Western Australia

J. McD. Stewart and Sherry L. Cunningham


 
ABSTRACT

In 1983 eight F1 hybrids were grown at Athens, GA from four B line strains of cotton crossed reciprocally with Dixie King ne restorer which has G. harknessii cytoplasm. The four F1's with Dixie King ne restorer as the female parent showed lateness and a lower yield than the four F1's where the B lines were used as female parents. Fiber properties of hybrids were essentially identical except the micronaire values for the lint from Dixie King ne restorer as the female parent was lower. Apparently this was due to the fact that the bolls were late in developing in the hybrids with G. harknessii cytoplasm.

In 1984 several reciprocal crosses were grown at Athens, CA and a few at Midville, CA.

At Athens, GA in 1984 the hybrids with restorer strains as the female parent showed significantly less percent of total yield at first harvest and also showed a significant reduction in total yield as compared to hybrids with B lines as the female parent. Lateness was also observed at Midville, GA but the small number of plots restricted any accurate determination of total yield.

At both Athens and Midville the percent lint was determined over several harvest dates. F1 hybrids produced from restorer strains as the female parent showed a significant increase in lint percent at both locations. The difference in percent lint in reciprocal. Crosses was greater for crosses with restorer Dixie King ne than for reciprocal crosses with a newer restorer 3-2546-2. That is, 3-2546-2 was selected after three additional backcrosses with G. hirsutum.

F1 hybrids made by crossing A lines with the restorer strains did not show the same degree of lateness nor reduction in yield as did F1 hybrids of the restorer strains x B lines. One possible for these differences is that restorer strains do not have exactly the same cytoplasm as A lines because a very small amount of cytoplasmic material is being transmitted by the B line male gametes. The A lines used in making the hybrids had been backcrossed to G. hirsutum about 16 times whereas the Dixie King ne restorer had been backcrossed to G. hirsutum about five times. Some researchers are of the opinion that there is mounting evidence of cytoplasmic material being transmitted by the male gametes. Perhaps the overall performance of hybrid cotton produced on CMS lines will improve slightly as we make additional backcrosses of both R & A lines with G. hirsutum.



Reprinted from 1985 Proceedings: Beltwide Cotton Production Research Conferences pp. 73 - 74
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998