Research on tetraploid maize with Opaque-2 endosperm

Abstract

Maize (Zea mays L.) is considered a diploid species (2x=20). In the experimental polyploid series of maize, the only forms of practical importance are tetraploids (4x = 40). The first tetraploid forms of maize were obtained by L. F. Randolph in 1932 by temperature shock. These maize cytotypes have valuable morphological, physiological and biochemical traits but show reduced fertility, slower growth, longer growing season, low productivity, which make them uncompetitive with diploids. However, scientists use them in different research programs regarding genetic variability, inbreeding and heterosis, genomic imprinting, gene expression, dosage effects etc. Also, some researchers from Russia succeeded in obtaining tetraploid maize populations on a broad genetic base, including introgression of teosinte, that have high productivity, protein content and are drought resistant.