II.40 Protein estimation in induced autotetraploids of Notch-2, a high protein high lysine mutant of barley.
S.P. Tiwari, H.C. Bansal and R.A. Pai. Division of Genetics and Nuclear Research Laboratory, Indian Agricultural Research Institute, New Delhi-110012, India.
Autotetraploidy was induced by colchicine treatment in Notch-2 mutant of barley which has been reported to have high protein and high lysine (Bansal 1970, 1974). The seven autotetraploids isolated by cytological identification were used for raising subsequent generations. Even though there was segregation for aneuploids with chromosome numbers ranging from 26 to 30, the most predominant type was the tetraploid with 28 chromsosmes in different generations.
Protein estimation was carried out in plants from each generation by a Technicon autoanalyzer and the results are presented in Table 1. In addition to the tetraploids protein estimation was also carried out in aneuploid plants with chromosome numbers 2n=27 and 29. In both the generations the tetraploid plants consistently showed 30 to 50 per cent more protein compared to the diploids. Protein content in aneuploids with 27 chromsosmes were found to have a near tetraploid value whereas in 29 chromosome plants the protein level was lower than the tetraploids but higher than diploids.
Table 1. Protein content in diploids, autotetraploids and aneuploids
Analysis of protein fractions in the original variety NP113, Notch-2 mutant and its tetraploid showed marked increase in the albumin as well as glutelin fractions in the tetraploid. There was a decrease in globulin and prolamin fractions (Table 2).
Table 2. Grain protein fructions (%) in NP 113, diploid Notch-2 and autotetraploids
The grain weight in tetraploids and diploids was comparable whereas seed fertility in tetraploids was lower than diploids. Selections are being made to improve the seed fertility. Attempts are also being made to develop triploids and trisomics from these autotetraploids to correlate ploidy and protein quantity and quality.
References:
Bansal, H.C. A new mutant induced in barley. Curr. Sci. 39 : 494, 1970.
Bansal, H.C, Induced variability for protein quantity and quality in barley. Indian J. Genetics 34A : 657-661, 1974.
