FUNCTION OF CAROTENOIDS IN PHANEROGAMS 



breeding of tomatoes and selection for preferential production of single 

 carotenoids has already been considered on p. 68. Y and y are to 

 some extent responsible for the skin colour by controlling the produc- 

 tion of an alkali-soluble, non-carotenoid pigment, which accumulates 

 in the skin. ^ ^ ^ 



VARIETAL DIFFERENCES 



Considerable varietal differences in carotenoid content have been 

 noted in forage grasses, * ^ tobacco leaves, i ^ 2, 1 4 2a carrots, 1 * 3- ^ ^ ^ 

 maize, 131,132 oranges, ^ * ^ tomatoes, 3 s, 1 4 7 p^as, ^ ^ ^ mangoes, 1 « 9, 1 5 

 and wheat. ^ '' ^ Little or no differences are reported in red 

 peppers, 1 3 3, 1 5 2 beet, ^ * '" and possibly also in peas. ^ * ^ 



There is no doubt that varietal factors far outweigh environmental 

 factors and the best chance of producing high carotenoid-containing 

 crops is by breeding. 1 4 4, 1 4 e, 1 4 7 Kohler et al.'^^'^ have by extensive 

 crossing produced a tomato [Baltimore X Fi x L. hirsutum P.I. 

 126445] containing 101 [i-g./g- of crude carotene (88 per cent, (^-carotene) 

 the value for the usual commercial tomato being about 6 ag./g- Perhaps 

 the most interesting point about this is that the carotene may be 



Table 1 1 . — Carotenoid Content of some varieties of Mango Fruit* 



* From Sadana, J. C, and Ahmad, B. (1946), Indian J. Med. Res., 34, 69, 

 and Chaudhary, M. T. (1950) J. Set. Food Agric, 1, 173. 



81 



