28 . HINDI COTTON IN EGYPT. 



sprin<>' if any complete eliiiiinatioii of the Hindi cluiracters is ex- 

 pected." 



The tendency to revert to small bolls is one of the most frequent 

 and least obvious evidences of Hindi contamination. Small bolls 

 can often be found on large-boiled plants, but many individuals pro- 

 duce only small bolls. The shape of the bolls may not suggest Hindi, 

 though other Hindi characters may be found, such as naked seeds, 

 sparse white lint, or pale spots in the flowers. 



To make a complete enumeration of all the plants that show any 

 of the Hindi characters it would be necessary to watch a field of 

 cotton through the whole season, for in some plants only the lint and 

 the seeds may betray the Hindi ancestry. Already, at the beginning 

 of the fruiting season in Egypt, it became evident that many of 

 the aberrant Egyptian plants were really Hindi liA^brids, in addition 

 to the type of hybrids that had been included in the countings. 

 Even in the fields that had been quite carefully rogued, as at Man- 

 surah, so that only very small percentages of plants with the Hindi 

 foliage were left, many white-flowered individuals remained. The 

 leaves of the white-flowered plants seemed to be a little broader than 

 those of adjacent yellow-flowered Egv'ptian plants, but the difference 

 was not enough to be noticed if attention had not been attracted by 

 the fioAvers. 



COHERENCE OF CHARACTERS IN HYBRIDS. 



It is not 3^et certain that all of the more Hindi-like hybrid plants 

 are realh^ first-generation In^brids, the direct result of cross-fertiliza- 

 tion between Hindi and Eg^q^tian plants. All that is known at pres- 

 ent is that the crossing of Eg^q^tian with Hindi does produce plants 

 of the Hindi-like hybrid type. The experiment has been made in 

 Egypt by Mr. Balls and in Arizona by Messrs. McLachlan and 

 Meade. It is possible, however, that some of the Hindi-like hybrid 

 forms ma}'' represent the progeny of hybrid parents. According to 

 the Mendelian theory of heredit}' a part of each generation of h}^- 

 brids should resemble the first generation, while the remainder 

 should show other combinations of the parental characters. In typi- 

 cal Mendelian hj'brids the contrasted parental characters are sup- 

 posed to have entire freedom of chance combination in the second 

 and later generations. 



In reality there does not seem to be such complete freedom of com- 

 bination of the two sets of characters that represent the two parental 

 types. Plants that have the Hindi foliage, or that of the Hindi-like 

 hybrid type, invariably have the white petals of the Hindi cotton. 



" Cotton Selection on tbo Farm by the Characters of the Stalks, Leaves, and 

 Bolls. Circnlar No. 06, Bureau of Plant Industry, U. S. Dept. of Agriculture, 

 1910. 

 210 



