274 



The Journal of Heredity 



inhibit the growth of seeds and promote 

 that of pulp to produce good bananas. 

 Effective causes are sterility produced 

 by hybridization, and improvement by 

 asexvial reproduction." Both of these 

 means may have been used by the pre- 

 historic ]3iant-brccders of the tropics. 

 Cross-pollination between different spe- 

 cies would easily take place, and would 

 result in at least partial sterihty of the 

 l^roduct. These hybrids, asexually 

 l^ropagated either by man or by nature, 

 would retain their sterility, and a 

 "horticultural variety" would be estab- 

 lished. Beccari's own idea is that all 

 the bananas of today are. in fact, the 

 results of hybridization of various 

 original wild forms which have now 

 disappeared. This in itself would be 

 sufficient to explain the seedless condi- 

 tion of the fruit of commerce; while the 

 numerous seed-bearing species found 

 wild at present are accounted for by 

 Beccari's hypothesis that they repre- 

 sent the product of one of the normally 

 sterile forms pollinated from some 

 species sufficiently distinct to cause 

 the production of normal seed. 



VAGARIES or POLLINATION. 



This hypothesis, although somewhat 

 unusual, "is given color by recent work 

 in Jamaica, described by Fawcett.' 

 Experiments in pollenizing the ordin- 

 ary, sterile varieties, at the Hope 

 Gardens, were unsuccessful until pollen 

 from the distinct but equally sterile red 

 banana (var. rubra) was used; the 

 nomially seedless commercial bananas 

 then set a full complement of seed. He 

 quotes a similar observation from A. 

 d'Angremond^: "Most of the pollen of 

 the Jamaican and Apple bananas is 

 sterile, and only a few of the ovules in 

 those plants have an embryo sac. How- 

 ever, dusting the ovaries of these culti- 

 vated fruit plants with pollen of Musa 

 basjoo and M. ornata [two wild species] 

 was sufficient to produce seeds."* 



Seeds may be produced in an ordi- 

 narily sterile variety as a result of 

 environmental conditions, if there is 

 any basis of fact in the story given to 

 O.' W. Barrett' by a Porto Rican 

 native, who advised: "Get a stool of 

 bananas growing rapidly in shallow soil 

 by the addition of artificial fertilizers; 

 let one bunch of fruits set; but before 

 that ripens, cut down all but one of the 

 stems in the clump. The remaining 

 shoot, 'thinking it has but one more 

 chance to perpetuate its kind before 

 being killed,' on account of the tre- 

 mendous shock to the more or less con- 

 nected stem bases in the ckmip. at once 

 jDroduces a small bunch of somewhat 

 abnormal fruits, some of which will 

 contain seeds." "As a matter of fact," 

 Barrett adds, "it is a usual thing to 

 find seeds in the commonest of the 

 Philippine bananas, the Saba." 



The origin of the present seedless 

 varieties is explained by many writers 

 as a matter of simple selection, rather 

 than of hybridization. The knowledge 

 which we are gradually acquiring of the 

 results of plant-hybridization, however, 

 makes it seem plausible that some cross 

 was the starting point from which the 

 tropical native began his process of 

 selection. The little knowledge we have 

 of the agricviltural skill of primitive man 

 gives aljundant reason to bclic\x him 

 intelligent enough to ])ropagatc choice 

 strains of his staple crops by oft'shoots. 

 In the banana Nature herself showed 

 him the way: for in addition to seeds, 

 which must always have been the nor- 

 mal method of reproduction, the banana 

 could ]jropagate itself rapidly b\' suckers 

 — unless the ijrimiti\'e types were very 

 diflerent from those we know today. 

 Around the base of the plant numerous 

 small suckers are thrown up; these, it is 

 believed, finally sej^arate themselves 

 from the parent, by the formation of a 

 layer of abscission-cells, and roll down 

 hill (when the i)lant is growing on a 



'Fawcett, William. The Banana. London. I'M.v 



*Ber. Hot. Ges. XXX, 686. 



^I owe to A. B. Stout, Direetor of tlie Lal)orat()ries at the New \ ork Botanic- Ciaiden, the 

 following rcferenee: "G. Tischler, Archiv. Zellforsehung .S:62 2-670, l')l(). Tisehler investigated 

 three races of Musa sapienlum and found that tlie elironiosonie numbers were ri'S])eeti\-ely 8, 

 16 and 24, and that the volume of the nuclei was proportionately 1 :2:,^. He found irregularities 

 in the development of pollen. S(jme chromosomes laggi'd behind and formed extra nuclei. 

 Often eight jiollen grains are formed from a single-mother cell. I believe this is all the cytological 

 work that has ever been done on any of the bananas." 



^Philippine Agric. Review, V, 383, 1912. 



