Wednesday, November 15, 2006

Amylose Content in Amylomaize VII Varied in Different Generations and at Different Locations.

Yusheng Wu1, Mark Campbell2, Yang Yen1, Dawn Gustafson1, and Zeno Wicks III1. (1) South Dakota State Univ, Box 2140-C, Northern Plains Biostress Laboratories 134, Brookings, SD 57007, (2) Truman State Univ, Div of Science, Kirksville, MO 63501

Abstract    Amylose has a number of specialty uses in production of such things as biodegradable plastics, adhesives, and other applications. Starch of amylomaize VII corn contains at least 55% amylose. Amylose content is controlled by the Waxy1 (Wx1) gene. The action of Wx1 is quantitatively conditioned by modifier genes, which have not been well characterized. In this study the inheritance of these modifier genes was elucidated with a generation means analysis specific for triploid endosperm tissue. Seeds of individual ears of P1 (H99ae, 55% of amylose), P2 (GUAT209ae, 70% of amylose), F1 (H99ae x GUAT209ae), F1r (P2 x P1), F2 (self F1), F2:3 (self F2), BC1P1 (F1 x P1) and BC1P2 (F1 x P2) were sampled at two locations (Brookings, SD and Kirksville, MO) in 2005. Purified starch from the seed samples was analyzed using a colorimetric amylose-iodine method following laboratory wet-milling of the corn. Amylose content in both parents was constant across locations but significantly different from each other. The amylose content of the F2:3 at the two locations (n=315 in SD and n=283 in MO) both showed normal distributions between about 55% of P1 and about 70% of P2. The F2:3 means and variances were 68.5% and 34.92 in SD, and 63.0% and 29.01 in MO, respectively. Sixteen transgressive individuals in SD and seven in MO were found. The maternal effects on amylose content and interactions between genotypes and environments were observed at the two locations in terms of the mean differences of those generations. There was no correlation between amylose content and plant height, ear height or 100-kernel weight. Broad sense heritability of amylose content was high in SD and low in MO. Regression models established should predict amylose content of unknown samples.

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