241 



or only partially rq^rodncilile. The chances are that, in their 

 ensemhle, they are not reproducible, for the factors which enter 

 into play are many, e.g. heat, mioisture, constitution of the soil, 

 pollinating insect life, and processes of cultivation are among the 

 factors that work for divergences, and that affect the behaviour 

 ■of the plant under altered conditions. There is, then, nothing 

 surprising in the fact that the Lima bean, in its transfer from a 

 temperate and relatively dry climate to a tropical and moist one, 

 should suffer a decline from the parent seed. The question is 

 whether, under successive generations of cultivation, the decline is 

 continuous. If this were so, it would, of course, imply progressive 

 degeneracy in the seed and the inadaptaljility of the Lima bean to 

 our local conditions since reproduction of a seed true to type is 

 ihe test of adaptability to surrounding conditions — of acclimatisa- 

 tion. 



^ow tests C and D seem to support the contention that the 

 Liima bean does, in effect, lose in weight from one generation to 

 the next. Here we have 2 lots of beans gathered off the same plot 

 one belonging to one generation containing 910 beans to^ the pound 

 — tlie second lot belonging to the following generation containing 

 1103 beans to the pound that is to say that the latter is 20% 

 lighter than the first. 



This may appear to clinch the matter and finally to settle the 

 point of degeneration in the seed. But does it? The writer 

 would be quite prepared to admit it, were it not for the adverse 

 ■conditions under which the later crops have been reared — condi- 

 tions which the above digression was meant to make clear. 



As can be seen by visitors to the Economic Gardens, the culti- 

 Tation of the various plots has been as thorough as it is possible to 

 make it in this country and some of the standing crops, ragi, hill 

 paddy, cholam (Sorghum vulgare), new to the land and, so far, 

 immune or at least partly so. to the pests tliat infect the land, 

 show quite adequate returns, ))irds notwithstanding. But in the 

 ■sections where bean cultivation has been going on now for several 

 months, the fight is all but liopeless. Nematodes, the Agromyza 

 fly, Bruclius rufimans, also a l)lack bug, round-bodied with shiny 

 carapace, the name of which is not known to the writer, leaf fungi 

 and root fungi have made a set-attack on these plots. Disinfec- 

 tion of seeds, sprayings with Bordeaux mixture and with in- 

 ;secticides, sulphur dustings, ])etroleum emulsion, neem oil emul- 

 sion., have been used without interruption, all witli only very partial 

 effect. 



Referring again to the tests given above, tlie figures under A 

 appear to negative the degeneration of the Lima bean from the 

 third generation to the fourth generation : these weights were taken 

 before the various ahove pests had taken such a hold of the land, 

 hut, unfortunately, it was found impossible to carry on these com- 

 parative tests with the later crops as the i:)ercentage of damaged 

 beans was too great to make the tests of any use. 



Test E was made from seeds obtained from the smaller plot 

 previously referred to ; but the test is inconclusive from the fact 



