Interspecific hybridization between Corchorus olitorius Linn. and C. capsularis Linn. and the cytogenetical basis of incompatibility between them

The pollen grains of Corchorus olitorius and capsularis (jute) germinate within ten minutes in cross-pollinations as well as in self-pollinations. No perceptible difference is observed in the number of capsularis pollen grains germinating on olitorius stigmas and vice versa, though an olitorius stigma (being bigger) accommodates more pollen than capsularis.Several hundreds of flowers of different capsularis types were pollinated with those of olitorius and vice versa for three years. Very small quantities of seeds are produced in the cross-pollinations compared to self-pollinations. The percentages of empty, partially full and full seeds produced vary greatly in different crosses including their reciprocal ones. Most of the seeds obtained are shrivelled and empty. Few apparently normal looking full seeds, more or less of the same size in appearance as selfed ones that are produced in certain crosses, weigh less than the same number of selfed seeds of the respective female parents concerned; this suggests the under-development of the embryo or/and endosperm. The seeds do not germinate. Even in spite of including some types of capsularis closer to olitorius in certain characters and the wild types of both species in the crossing programme, still there was no success in getting hybrids between the two cultivated species of jute. Style reduction methods also fail. The possibilities of getting hybrids between them are indicated.

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Samenvatting Getracht is de soortskruising van Corchorus olitorius x C. capsularis tot stand te brengen. Voor de veredeling van jute (o.a. op ziekteresistentie) zou dit belangrijke perspektieven kunnen bieden.Ofschoon wel enig zaad verkregen werd, gelukte het toch niet daaruit F₁ planten op te kweken. Bij de voortzetting van het onderzoek zal gezocht worden naar methoden om de beide soorten toch te overbruggen.

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Department of Agriculture, Calcutta University