Phosphate utilization and constitutive synthesis of phosphatases in Thermoactinomyces vulgaris Tsilinsky

Thermoactinomyces vulgaris utilized both organic and inorganic phosphates with equal efficiency for its growth. The specific activities of the thermophilic acid and alkaline phosphatases were found to be maximum at 1 mM concentration of each phosphate source. All the phosphatase isoenzymes (three alkaline and one acidic) were observed irrespective of the substrate source and concentration, suggesting constitutive synthesis of the enzymes. During growth and differentiation, both acid and alkaline phosphatases exhibited uniformly stable patterns of isoenzymes with slight variations in their specific activities.

Mode of inheritance of dwarf stature and allelic relationships among various spontaneous and induced dwarfs of cultivated rice Oryza sativa L

Genetic study of spontaneous and induced dwarfs included the mode of inheritance of dwarf stature and the allelic relationships among various dwarfs. Qualitative genetic analysis involving crosses of fourteen dwarfs with a common tall variety 'IARI 11124' showed that the degree of dominance in the F1 hybrids varied with the cross. With the exception of the crosses of IARI 6579 and IARI 10560 with the tall variety, all crosses exhibited incomplete dominance. The segregation pattern in F2 populations of height classes showed dwarfness to be a monogenic recessive trait functioning, however, in association with modifier complexes of varied strength. From F2 behaviour of all possible crosses involving the fourteen different dwarfs, the allelic relationships were deduced. Three major groups of dwarfs could be recognised. Group I, comprised of FF 36, IARI 5842, IARI 5906-2B, IARI 5923, IARI 10061, IARI 10560 and IARI 11445, was allelic to I-geo-tse and Dee-Gee-Woo-Gen with modifiers of predominantly negative effects, while group-2, comprised of dwarfs IARI 5901-2, IARI 5924, IARI 6579 and IARI 7312B, was also allelic to Dee-Gee-Woo-Gen and I-geo-tse but with large and equal number of modifiers of positive and negative effects. The induced mutant, Central Africa Mutant (CAM) which constituted the third group seemed to possess a dwarfing gene that was non-allelic to those of the above mentioned two groups of dwarfs, with equal strength of modifiers of plus and minus effects. Unlike the dwarfs of spontaneous origin, which are invariably allelic to 'Dee-Gee-Woo-Gen', the induced dwarf was nonallelic. Thus, induced mutagenesis appears to give rise to dwarfing genes different from those found in the naturally occurring dwarfs.

Combining ability studies in Pearl millet (Pennisetum typhoides (Burm.) S.& H.)

A line x tester analysis of combining ability involved five male-sterile lines from different sources and 10 inbreds of Pearl millet developed at Hissar (India). Additive x additive and additive x dominance types of gene interaction were found to predominate in the material under study. A high degree of association was found between general combining effects and the mean performance of lines and testers over crosses but no association was observed betweenper se performance of the crosses and their specific combining ability effects. Among the male sterile lines, L-110 proved to be the best general combiner, whereas H-297, followed by H-198, was the best of the inbreds. The crosses L-110 x H-440, L-110 x H-406, 18D2A x H-297, 18 A x H-198 and L-110 x H-297, were superior to the released variety, Hybrid-1, used as control.