بیوتکنولوژی و بیوشیمی غلات (Jun 2022)
A review of the background and breeding methods of sweet corn
Abstract
Sweet corn, Zea mays Var. Saccharata is the youngest form of corn that arose after an accidental mutation in the common corn, and the Native Americans and Indian tribes began to cultivate it after becoming aware of the differences. The first registered variety of sweet corn was named Black Iroquois by European settlers in 1779. In the 19th century, white OP (open pollination) cultivars became popular in the United States. Two varieties of this type that are still cultivated and consumed are the Country Gentleman variety (with elongated and small seeds and irregular rows, also called Shoepeg corn) and the 'Stowell's Evergreen' variety. Scientific developments in the field of plant breeding, including the hybridization technology by inducing traits such as ripening at the same time and improving the quality of cobs and resistance to diseases, created tremendous changes in the production of sweet corn in the 20th century. This article with an overview of the successes achieved in creating new cultivars and improving the quality and marketability traits of sweet corn, its genetic differences from common corn, and the role of hybridization as one of the common tools of classical breeding to achieve superior genotype qualities are emphasized in sweet corn. Classification of sweet corn hybrid cultivars based on factors such as genes affecting carbohydrate metabolism and endosperm sugar percentage, planting time until harvest, seed color (yellow, white, pink, purple, and black), cob shape, and type of consumption (freshly eaten, Freezing, canning and exporting) forms another part of this article. Examining sweet corn breeding methods shows that despite the use of a number of specific techniques and theories, due to the different results of each method, the effect of external pollination, and the high perishability of the final product, Sweet corn breeding is very different in practice. The most important methods in sweet corn breeding have been reviewed in another part of this article. These methods include pedigree breeding, production of synthetic and composite masses, backcrossing and breeding with the help of molecular markers, as well as selection for some special traits such as edible quality, seed production, improved germination in Sh2 seeds, and resistance to pests and pathogens. In the final part, all kinds of sweet corn varieties, including commercial hybrids for fresh consumption and hybrids suitable for processing, have been introduced according to the genetic changes that have taken place in sweet corn cultivars since long ago.
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