Factors Limiting the Cultivation of Egyptian Cotton Under North Indian Conditions

This paper deals with a study of factors limiting the cultivation of some Gossypium barbadense varietiet under North Indiad conditions. Seventy genotypes grown in 1968 could be classified into (i) early non-branched clustered typs from USSR; (ii) medium maturing normal branched types from U.S.A. (iii) late maturing tall normal branched and photosensitive types from Egypt UAR and Sudan. All of them are poor yielders. Varieties from group (i) and (ii) though they flowered 93–97 days after sowing did not set any bolls. Studies on pollination and fertilization of Russian and American varieties revealed that during 4th week of August 1970 though the germination of pollen was normal on the stigma yet the percentage of fertilization of ovules was very poor, causing poor boll set. During the first week of October, 1971 the same varieties started setting bolls; greater percentage of ovules were fertilized during this period. Consideration of the meterological data suggested that it is the night temperature which has gone down during the second flowering flush and this might have caused the difference in the fertilization of ovules and probably boll setting. It has been suggested that higher night temperature affects pollen tube growth in barbadensee ottons.