Xenia effect in modified endosperm texture opaque-2 maize

Seven non-modified endosperm texture opaque-2 inbreds (ROh43o2, RA619o2, RMo17o2, B57o2, B45o2, B46o2, and RN28o2) and four modified endosperm texture opaque-2 inbreds (RM14mod.o2, ROh45mod.o2, RVa35mod.o2 and RSyn-B-3mod.o2) were selfed and crossed reciprocally to study xenia effects of endosperm modification and other traits. The traits measured were endosperm modification, kernel density, protein content, lysine/protein ratio (L/P), zein protein and free amino acids. The degree of endosperm modification was measured by the proportion of modified kernels in a 100K sample. An eleven class scale was used (class 0 = 5% or less modified kernels, class .5 = 5-10% modified to class 5 = 90-100% modified). The selfed seeds of all the non-modified and modified opaque-2 inbreds showed major differences for all traits except kernel density (Table 1). The reciprocal F1 seeds showed differences in degree of modification, zein and free amino acids (Table 1). These differences could be the result of dosage, maternal effects, or xenia effects. The xenia effects were measured by comparing the differences between selfed and F1 seed average over the different crosses and selfs. These differences are presented in Table 2.

The reciprocal F1 seed expressed significant differences in all traits except when the modified endosperm texture opaque-2 inbred was used as the female parent. When the modified endosperm opaque-2 inbreds were used as pollen parents, the F1 seed showed differences from the non-modified female parent endosperm for all traits. These results indicate that in addition to dosage effects, xenia effects can also exist in modified endosperm texture opaque-2 materials.

Table 1.

Table 2.

T. M. Sung


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