Characterisation and evaluation of the rice cultivar njavara

Abstract

Characterization and evaluation of the rice (Oryza saliva L.) cultivar Njavara was undertaken in the Department of Plant Breeding and Genetics and Biochemistry Laboratory, College of Horticulture, Vellanikkara during 1997-1999 with an aim to characterize Njavara genotypes based on morphological and biochemical studies and to evaluate its nutritional qualities. Morphological characterization indicated that the thirteen Njavara genotypes were distinct among themselves and the Njavara genotypes NI (Njavara type from Mulloorkara, Thrissur), N2 (Njavara type from Chittoor, Palakkad), N5 (Njavara type from Edavanna, Malappuram), NIl (Njavara type from Pattambi, Palakkad) and NI3 (Njavara type from Thootha, Palakkad) yielded on par with the check variety Ptb-IO, eventhough they were having extra short growth duration compared to Ptb-I 0. Biochemical characterization revealed the possibility of utilizing peroxidase, esterase and protein polymorphism for identifying the Njavara genotypes especially NI (Njavara type from Mulloorkara, Thrissur) , N2 (Njavara type from Chittoor, Palakkad), N3 (Njavara type from Chittoor, Palakkad) and N4 (Njavara type from Chittoor, Palakkad) and also for the identification of Njavara as a cultivar. Selecting some other isozymes coupled with enzyme activity studies and opting for molecular markers were the other strategies suggested for characterization of Njavara genotypes. Majority of the Njavara genotypes expressed high protein content than Ptb-l O. The genotypes N2 (Njavara type from Chittoor, Palakkad) and N8 (Njavara type from Alwaye) were recommended to be included in weaning and invalid foods due to high protein content. The genotypes N2 (Njavara type from Chittoor,

Palakkad), N3 (Njavara type from Chittoor, Palakkad) and NI2 (Njavara type from Thrissur) appeared to have higher number and content of free amino acids. Most of the Njavara genotypes had intermediate amylose and as such may not have any problem with respect to consumer preference. Starch grain characterization revealed that starch grain size could be used for varietal characterization in conjunction with morphological and biochemical markers. Absence of flavonoids in Nj avara grain indicated its nonaromatic nature. The genotype N7 (Njavara type from Tellicherry, Kannur) was found to have better digestibility due to low amylose content, high amylase activity and high soluble carbohydrate content. Variability studies indicated that fat content, straw yield and grain yield provided a good genetic base for selection. Correlation and path studies revealed that grain yield could be improved by simultaneous selection for high straw yield and longer leaves while selection for wider leaves, longer ligules, increased number of days to 50 per cent heading, longer panicles and long duration genotypes favour high free amino acid content. Low amylase activity, short and narrow leaves, shorter panicles, low 1000 grain weight, slender grains, short duration genotypes and smaller starch grains were observed to favour high protein content and selection for tall culms, high 1000 grain weight and bold grains was found to favour high amylase activity: