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26 Pages

Current Researches in Hybrid Broccoli

SUMMARY. Broccoli is the most nutritious member of Cole group be­ longing to family Brassicaceae. Its marketable plant part is “head” com­ posed of immature flowers or florets. It is very popular in the developed world because of its highly nutritional and medicinal properties. It is rec­ ommended for consumption as a measure to decrease the incidence of human cancer. Different types of broccolis are available but green types are more popular. Genetic resistance is also available for many diseases. Self-incompatibility and male sterility are also present in the crop. Com­ mercial heterosis is reported by many workers. The use of self-incom­ patible and cross-compatible lines and genic and cytoplasmic male sterile lines helps in the seed production of hybrid varieties. Many hy­ brids have been released for commercial cultivation and hybrid seed production is successfully exploited. [A rticle copies available fo r a fe e from The Haworth Document D elivery Service: I-800-HAWORTH. E-mail address: <[email protected]> Website: <http://www.HaworthPress.com> © 2004 by The Haworth Press, Inc. All rights reserved.]

KEYW ORDS. Broccoli, Brassicaceae, genetics, heterosis, self-incom­ patibility, male sterility, seed production, hybrid seed production

INTRODUCTION

Broccoli (Brassica oleracea L. var. italica Plcnck.) is an Italian word from the Latin brachium meaning an arm or branch (Boswell, 1949) and is used in Italy to refer to young edible floral shoots on brassicas, but commonly refers to sprouting and heading forms of italica group of Brassica oleracea L. (2n = 2 x = 18). It is a cool season crop and its most types are biennials. It is the most nutri­ tious member of Cole group belonging to family Brassicaceae. Its marketable plant part is head composed of immature tlowers or florets. There is consider­ able diversity in cultivated Coles, with different parts of the plant being used for consumption as vegetables. In broccoli and cauliflower, the developing in­ florescence is the edible part and in this respect the two crops are very similar. Due to this apparent similarity, there is considerable confusion that existed in both scientific and lay nomenclature, since the two terms (broccoli and cauli­ flower) were being used interchangeably. A practical distinction between the two could, therefore, be made on their comparative ontogeny at marketable maturity (Gray, 1982; 1989) when cauliflower head is a curd or dome of tissue made up of a mass of proliferated floral meristcms (Sadik, 1962), of which 90 percent or more abort prior to flowering (Crisp and Gray, 1979) whereas in broccoli the head and sprouts are actually composed of fully differentiated flower buds of which relatively few abort prior to flowering. The marketable stage in cauliflower is, therefore, ontogenetically at quite early stage than that o f broccoli.