Starch Particle Volume in Single- and Double-Mutant Maize Endosperm Genotypes Involving the Soft Starch (h) Gene
- O. A. Gutiérreza,
- M. R. Campbellb and
- D. V. Glover *c
- a USDA-ARS, Crop Science Res. Lab., Genetics and Precision Agriculture Research Unit, Mississippi State, MS 39762
b Truman State University, Division of Science, 162 Barnett Hall, Kirksville, MO 63501
c Dep. of Agronomy, 1150 Lilly Hall of Life Sciences, Purdue University, West Lafayette, IN 47907-1150
Larger starch particle volume of maize (Zea mays L.) endosperms is beneficial for many aspects of starch processing, and may improve the performance of some starch attributes. The recessive soft starch (h) locus increases starch granule size compared with normal (+/+) genotypes. The objective of this study was to compare starch particle volume of normal maize inbreds, and their near-isoline conversions to single- and corresponding double-mutant endosperm starch genotypes, including the h locus. Eighteen public inbreds and their near-isogenic conversions to amylose-extender (ae/ae), dull (du/du), waxy (wx/wx), sugary-2 (su2/su2), h/h, ae/ae h/h, du/du h/h, wx/wx h/h, and su2/su2 h/h, were planted in replicated trials in two environments in 1995 and one in 1996. Starch was extracted from mature kernels collected from each plot and examined for starch particle volume with a laser-based, particle size analyzer. Starch particle volume was greater in all near-isogenic line conversions containing the h locus than in their respective normal inbred. Starch particle volume for all double-mutant h/h combination genotypes was greater across all inbreds than in their respective single-mutant starch counterparts. These results demonstrate that the h allele is epistatic to the ae, du, wx and su2 alleles for increasing starch particle volume. Starch particle volume for single-mutant genotypes averaged across inbreds and environments ranked from the smallest to the largest as follows: du/du, ae/ae, su2/su2, normal (+/+), wx/wx, and h/h The ranking among the double-mutant genotypes from smallest to largest starch particle volume was: du/du h/h, su2/su2 h/h, ae/ae h/h, and wx/wx h/h The epistatic nature of the h allele further enhances its usefulness for increasing starch particle volume in combination with other endosperm starch mutants utilized to develop specialty starches with value-added traits. This study also demonstrated that the genetic variation present among maize inbreds could be useful in breeding for increased starch particle volume.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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