INHERITANCE IN DOLICHOS LABLAB, L. PART I. 



By S. C. HARLAND, D.Sc. (Lond.). 

 Imperial Department of Agriculture for the West Indies. 



Introduction. 



The plant known as the bonavist or hyacinth he3in{Dolichos lablahjj.), 

 is widely distributed in tropical and sub-tropical countries. The young 

 pods are used as a substitute for French beans, and the beans themselves 

 are by no means unpalatable. When cooked they somewhat resemble 

 Lima beans in flavour. 



A large number of varieties have been collected from various West 

 Indian islands, and for other sorts the writer is indebted to the United 

 States Department of Agriculture and Messrs Ryder of St Albans. 



Pedigree cultures from single plants invariably breed true, and it is 

 probable that Dolichos lablab, like Pisum, is naturally self- fertilising. 

 Dehiscence of the anthers takes place at least one, and sometimes two 

 days before the flowers open. Several thousand plants have been used 

 in these experiments, and so far no case of natural crossing has been 

 recorded. The absence of natural crossing is not due to the absence of 

 insect visitors, for the large carpenter bee (Xylocopa sp.), which has 

 previously been noted by the writer (1919) as responsible for a consider- 

 able amount of ^natural crossing in the cowpea, visits the flowers 

 extensively. 



Waby (1917) considers that his type Dolichos lablab yax.macrocarpuin 

 resulted from a natural cross between the two varieties Park Runner 

 and Vilmorin's Stringless. This cannot be regarded as proven, although 

 it is not impossible that occasional natural crosses are effected through 

 the agency of thrips, which at certain times are very abundant in the 

 flowers. The time of dehiscence of the anthers varies somewhat in 

 different sorts, and this observation lends some support to the theory 

 that natural crosses are possible by the transference by insect agency 

 of pollen from an early dehiscing to the stigma of a late dehiscing 

 variety. 



