Vol. XVII. No. Ho. 



THE AGRICULTITIIAL NEWS. 



85 



Grouud provisions, especially potatoes, were more plentiful. 

 The general condition of the cotton crop was not good. 

 Exceptionally severe attacks of cotton worm were reported 

 from all iistricts. Onion caterpillars were also bad in all 

 places where onions were planted. The rainfall recorded for 

 the month was 168 inches, as compared with 2'9.5, the 

 average for this month for the preceding sixteen years. 



DOLICHOS HYBRIDS IN ST VINCENT. 



Among the leguminous plants used for human consump- 

 tion in the West Indies, the bonavist bean {Dolichos labhib) 

 is I me of the must valuable. It appeared, however, to the 

 ■writer, that better varietie.s than those at present cultivated 

 might be obtained through hybridization. An examination 

 of available material in November I 916 showed that there 

 were at least four ditierent types present in St. Vincent: — 



(1) A strong climber, devoid of anthocyauin colouration, 

 with yellowish-white seeds, white flowers, and small pods; 



ate flowering. (A). 



(2) An upright or bush form, devoid of anthocyauin 

 colouration, with yellowish-white seeds, white flowers and 

 small pods; early flowering. (B). 



(3) Resembling (A) but with broader pods and larger 

 seeds; late flowering. (C). 



(4) A rather weak climber, with a considerable develop- 

 ment of purple anthocyanin colouration, purple flowers, 

 purple pods, and black seeds slightly speckled with brown; 

 early Aowering. (1).) 



Of thfse. A, B, and C are in general use as food-plants. 

 Form D is chiefly used as an ornamental plant but Piev. 

 0. H. Branch states that this variety is also edible. 



In the spring of 1917 a variety knuwn as Di>lichos 

 gi^anteus was obtained from Messrs. Ryder it Sons, of 

 St. Albans. This proved to be quite different from the 

 types mentioned above. The habit was that of type B, but 

 less vigorous; the flowers were pale purple: the development 

 of anthocyanin colouration was feebly marked, the pods 

 being whitish instead of purple; the .seeds were black, slightly 

 speckled with brown. This type will be denoted by the 

 symbol (E). 



The following hybrids were made: A x D, D x B, and 

 D X E. In the F, generation of Ax I) the habit was 

 similar to .\, but more vigorous. Flowering did not take 

 place until the plants were several months old. The 

 ex:w;t date of flowering was not recorded, but the 

 late flowering habit certainly behaves as a dominant. 

 The development of anthocyanin colouration was intermediate; 

 the flowers were purple and indistinguishable from D; the 

 .seeds wfre black, slightly speckled with brown, an 1 indis- 

 tinguishable from those of D. 



In the F.^ gener-itio'i of A x 1), segregation in respect of 

 tke climbing habit, the time of flowering, and the development 

 of anthocy.Anii] colouration was observed. It appeared that 

 there was a genetic correlation between the pre.sence of 

 anthocyanin colouration in stem, leaves, and pod, and the 

 purple colouration of flowei- and black testa of the seed, i e. all 

 plants .showing any anthocyanin in stem or leaves possess 

 also purple fl nvers ,\nd black seeds speckled with brown, 

 whilst if a plant has no anthocyanin in stem c,x leaves, its 

 flowers are pure white, and its seeds are yeUowishwhite. 



The follnwin.; numbers were obtained: — 



Anthocyanin present in stem, leaves, and pods, tiowers 

 purple, seed bl.vk specklefl with brown, ■')9. 



Anthocyanin absent, tiowers white, seeds yellowish- 

 white, 12. 



This ratio approximates to the normal Mendelian 

 one of 3:1. 



No further studies were made with this cross. 



In the F, generation, of B x D, the climbing habit of 

 D was completely dominant. The amount of anthocyanin 

 colouration was again intermediate, the flowers being purple, 

 and the seed coat black, speckled with brown. 



In the F.^ generation B x D several hundred plants 

 were grown, and these were examined for (a) climbing or 

 dwarf habit, (b) pre.sence or absence of anthocyanin colour- 

 ation. It may be observed that the segregation of the 

 dwarf or bush habit was very sharp, and no difficulty was 

 experienced in classifying the plants. 



Climbing habit. Dwarf habit, 



Anthocyanin Anthocyanin Anthocyanin Anthocyanin 

 pre.sent. absent. present. absent. 



4:51 147 155 44 



Expectation on 9:3:3:1 basis. 

 4482 149-4 \U\ 498 



From these figures we are justifled in concluding, 

 tentatively at all events, that the pre.sence and absence of 

 anthocyanin colo'iration form a Mendelian pair, and, as was 

 found by Mendel himself in Fisum, another Mendelian pair 

 is formed by the climbing and dwarf characters. 



In regard to the economic aspect of this work, selections 

 are being made for yield and table qualities. Although this 

 work has nut proceeded very far as yet, the results are 

 encouraging. 



In the Jon ma/ of tlu Board of Agriculture of Brilish 

 Guiana for April- July 1917, .Mr. .J. F. Waby has descibed 

 a hybrid Dolichos whicli he calls DolicJws lablab, var. 

 macrocar/<a, Waby. This is said to be a natural hybrid 

 between two varieties known as Park Runner and Vilmoriti's 

 Stringless. So far as we can see, Mr. Waby has described 

 a heterozygous type as a new variety— a procedure of 

 doubtful biological validity. We await with great interest 

 an account of the behaviour of the F.^ generation from the 

 single F.J plant which he was able to save. 



In case any readers of the Agricultural News wish to 

 hybridize the bonavist bean, the following short account o) r.he 

 method adopted by the writer may be useful. Take a bud 

 which is unopened and the anthers of which are unburst, ind 

 with a needle carefully slit the edge of the keel, being careful 

 not to injure the stigma. Then with a pair of forceps, nip 

 oft' the anthers. On the following morning pollen from the 

 male parent may be applied to the stigma with a .iii.all 

 camel's hair brush. This method is quite easy, and 90 

 per cent, of succes.ses have been obtained thereby by the 

 writer 



S.C.H. 



The Antigua Government Granary. -Mr. k E. 



Collens, ■Acting Superintendent of Agriculture for the Leeward 

 Islands, r,.>ports thit unfortunitely the surface of the mill- 

 stones at the granary began to disintegrate towards the end 

 of February which spoile'l the meal with particles of grit. 

 This occurred in grinding h;ird imported corn. Orders have 

 been sent to England for duplicate sets of stones; and meio- 

 while it is hoped thit the present set may be able to d-?il 

 with local corn, which is not so hard as that impDrted. 



It is unfortunate tha" this break down should have 

 occurred just when the granary wis satisfaitorily prodaoing 

 from 800 to 9001b. of meal a div, and was proving o! arett 

 utility to the community. 



