Studies on kernel protein and phytic acid in teosinte derived s1 lines of maize (Zea mays l.)
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Date
2022-09
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G. B. Pant University of Agriculture and Technology, Pantnagar
Abstract
The investigation was carried out with the aim to transfer gene(s) responsible for high protein content in teosinte into the genetic background of inbred line LM14 which has low phytate content through repeated backcross breeding at Norman E. Borlaug Crop Research Centre and Department of Genetics and Plant Breeding, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar, Uttarakhand. The field experiments were conducted during kharif 2019, rabi 2019-20, kharif 2020, rabi 2020-21 and kharif 2021. The experiment was carried out with two populations that had same parents but followed 2 different crossing programs. It is apparent from the results that among the S1 lines of teosinte derived maize population, that there was an increase in mean protein of ~22% in both populations when compared to the recurring parent. The protein content ranged between 12.43% and 19.68% in 2227 {LM14x (LM14//LM14xPT) #F2} and 12.43 and 18.04% in 2228 (LM14//LM14xPT##F2). Of all the 137 lines of both the populations, three lines namely 2227-93, 2227-95, 2227-97 had protein content of around 19% and two lines 2228-60 and 2228-58 had protein content of around 18%. None of the S1 lines exceeded the protein content present in the donor parent teosinte, and the line which had the lowest protein content was still higher than the protein content LM14 in both populations. Investigation on phytic acid and total phosphorus have unequivocally demonstrated that the S1 lines produced in the genetic backgrounds of LM14 have much lower levels of phytic acid along with lower levels of total phosphorus. In the two populations under study S1 lines, 2227-22 (3.072 mg/g), 2227-69 (3.095 mg/g), 2227- 95 (3.059 mg/g), 2228-6 (2.967 mg/g), 2228-64 (2.955 mg/g) and 2228-50 (2.979 mg/g) were statistically comparable to the recurrent parent, while 2227-11(3.952 mg/g), 2227-16 (3.952 mg/g), 2227-27 (3.988 mg/g), 2227-29 (3.926 mg/g), 2227-86 (3.976 mg/g), 2228-18 (3.875 mg/g), 2228-39 (3.847 mg/g), and 2228-48 (3.835 mg/g) were all observed to be notably lower in levels of PA, compared to the parviglumis-teosinte parent. Lines namely 2227- 46 (0.77%), 2227- 67 (0.78%) 2227- 86 (0.82%), 2228-35 (0.78%), 2228-54 (0.77%) and 2228-65 (0.80%) had the highest level of P, and quite on par with that of the parviglumis-teosinte parent. Additionally the recurrent parent had the lowest P, with 2227-95 and 2228-6 being the closest with 0.41% and 0.40 % P. The most promising lines amongst all the teosinte derived S1 lines were analysed and grouped together using ward’s method of minimum variance, viz., 2227-22, 2227-64, 2227-69, 2227-77, 2227-93, 2227-95, and 2227-97 which had a mean protein content of 18.47 % with PA content of 3.1 mg/g and 3 lines from the second population i.e. 2228 had a mean protein content of 16.6% and a PA content of 2.97 mg/g, which were as follows 2228-6, 2228-50 and 2228-64.