Heritability of Nitrate Reductase and Cyanide Levels in Seedlings of Grain Sorghum Cultivars¹

Abstract

Seedlings of 41 cultivars of grain sorghum [Sorghum bicolor (L.) Moench] including 30 hybrids and all but two of their parents were grown in a growth chamber; harvested 10, 14, and 18 days after planting; and assayed for hydrolizable cyanide and in vitro and in vivo nitrate reductase activity (NRA). The genotype X age variance component was essentially equal to the genetic variance for each character, which suggest that genotype X environment interactions are major components of the phenotypic variance. Cyanide level was highest in 10‐day‐old plants and dropped sharply in 14‐day‐old plants. Broadsense heritability of hydrolizable cyanide was high (0.89 to 0.95) for all three ages of plants. Narrow‐sense heritability indicated the cyanide content of 10‐day‐old plants could be changed 0.76 units for each unit change in the midparental value, but expected progress decreased markedly for 18‐day‐old plants. Broad‐sense heritability of in vitro NRA was high at all ages, and narrow‐sense heritability was moderate to low. Thus, significant genetic advance could be expected from selection among pure lines and hybrids, but nonadditive genetic variance would reduce progress in hybrids based on selection of their parents to a moderate level. In vivo NRA was only 20% of in vitro activity. Heritabilities, in general, also were lower for in vivo than for in vitro NRA.

Inheritance of Seedling Hydrocyanic Acid Potential and Seed Weight in Sorghum‐Sudangrass Crosses1

“…Krauss (14), in a study not included in Nass's review, concluded that HCN-p was conditioned by four genes with additive effects without dominance. Other studies conducted since Nass's review reported different conclusions on the importance of additive and nonadditive effects (2,4,9). Recently, Gorz et al (10) found that seedlings of sorghum lines KS8 and N32 were high in HCN-p, but the HCN-p of flag leaves from field-grown plants of KS8 was only about 1/10 as high as that of N32 flag leaves.…”

Cyanogenesis in Turnera ulmifolia L. (Turneraceae). I. Phenotypic distribution and genetic variation for cyanogenesis on Jamaica

“…More recent studies of T repens have revealed that there are different functional alleles coding for the cyanogenic glycoside that result in the production of different amounts of the chemical (Hughes et al, 1984). Tn S. bicolor, cyanogenesis appears to be a polygenic trait (Nass, 1972;Eck et a!., 1975). Polymorphism for cyanogenesis has also been reported in natural populations of the bracken fern, Pteridium aquilinum (Cooper-Driver & Swain, 1976).…”

Cyanogenesis variation in the Turnera sidoides L. polyploid complex (Turneraceae)

“…Polymorphic populations, having cyanogenic as well as acyanogenic individuals, have been reported for some forage, crops and wild plants (Grant & Sidhu, 1967; Nass, 1972; Eck et al ., 1975; Hughes, 1991). In these populations acyanogenesis was attributed to the lack of β‐glycosidase but not of the cyanogenic glycosides (Kakes, 1990).…”