Pollen‐Parent Effects on Protein Quality and Endosperm Modification of Quality Protein Maize

Abstract

Quality protein maize (Zea mays L.) (QPM) has protein of high nutritional value conferred by the opaque‐2 (o2) gene and vitreous endosperm because of numerous modifier genes. Superior protein quality is only expressed when endosperm tissue is homozygous recessive (o2o2). During QPM research and development, it is common to evaluate trials in which QPM genotypes randomly interpollinate. We do not know if protein quality determinations for entries in such trials are valid measures of what would be expressed in a pure stand. In this study, we used nine QPM and three o2 (unmodified, soft endosperm) cultivars as females for six pollen treatments to measure the effect of pollen source on protein concentration of grain, tryptophan concentration in grain, tryptophan concentration in protein, and endosperm modification (translucency) in three environments. The pollen treatments were four QPM hybrids, one normal‐endosperm maize cultivar, and self‐pollination. Pollen of normal‐endosperm maize reduced tryptophan in grain by 37% and tryptophan in protein by 38% but improved endosperm modification of QPM females by 36% relative to pollen of QPM males. Pollen of normal‐endosperm maize and QPM did not differ in effect on protein concentration of grain. Protein quality traits did not differ for QPM cultivars pollinated by self or by other QPM males. Kernels were slightly more vitreous, however, for females pollinated by other QPM males than for those that were self‐pollinated. Effects of females were significant (P < 0.01) and the interaction of males × females not significant for QPM entries for all traits. We conclude that it is valid to evaluate QPM germplasm in trials where entries randomly interpollinate, provided that pollen of normal‐endosperm maize is excluded.

Genetic effects and genotype × environment interactions govern seed oil content in Brassica napus L.

“…Therefore, the selection for high-oil rapeseed would be more effective based on the photosynthetic activity of silique wall than based on the performance of maternal parent. It should be noted that xenia has a direct genetic effect on OC in many crops [11, 12, 46, 47], and is applied not only in genetic and physiological research but also in crop breeding and production. Similar to the case of corn and soybean, controlling the pollen source and considering xenia are required in both breeding programs and investigation of OC in rapeseed.…”

Genetic analysis on oil content in rapeseed (Brassica napus L.)

“…In many crops pollen parents have a direct genetic influence (xenia effect) on F 1 seeds (Song et al 1991;Pixley and Bjarnason 1994;Letchworth and Lambert 1998). For example, there was xenia effect on the oil content of corn, and which was estimated to be 0.35 (Song et al 1991).…”

Quality Protein Maize Germplasm Characterized for Amino Acid Profiles and Endosperm Opacity

“…Blocks were assigned as two replications per location. Due to the contamination of foreign pollen on the ear (xenia effect) that was observed during our 2010 pilot study and previously reported in other QPM studies (Hossain et al, 2008; Pixley and Bjarnason 1994), five (WE) or three (CS, AM) ears were randomly chosen for self pollination and harvested separately to mimic the effects of each hybrid planted in an isolated grower's field. At the WE and CS locations, all plots were hand harvested to obtain yield and composition data.…”