GENETIC VARIATION AND NATURE OF GENE ACTION IN ASSAM RICE FOR GRAIN ZINC CONCENTRATION AND BIOFORTIFICATION POTENTIAL
Loading...
Date
2023
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The cultivated gene pool of rice is deficient in most of the required
micronutrients. Zinc is one of the most important among these to mention about.
Twenty (20) percent of the world population is at risk of Zn deficiency resulting from
inadequate dietary Zn intake that causes stunted growth (Brown et al., 2009). Genetic
and agronomic manipulations for biofortification to raise the concentration of the
nutrients in the grain are suggested to overcome the problem. The present investigation
was undertaken to study genetic diversity for grain Zn in Assam rice germplasm and
also to explore the possibility of bifortification potential. A set of 29 ahu genotypes
randomly collected from different places along with the high yielding sali rice variety
Shraboni, known to be rich in Zn, were evaluated in 4 different micro-environments
created by differential application of Zn fertilizer in ahu season of 2019. Among these,
6 were randomly selected for combining ability studies through diallel mating system
without the reciprocals. Observations were taken on different morphological and quality
characters and the recorded data were subjected to different statistical analyses
following standard procedures. Out of 30 genotypes, 9 were grouped as low (<20 mg
1000g-1), 12 medium (20-30 mg 1000g-1) and 9 others were grouped as high (>30 mg
1000g-1) grain Zn genotypes as per their grain Zn content. Grain Zn content was found
highest (52.35 mg 1000g-1) in Shraboni and lowest (11.73 mg 1000g-1) in Basantabahar.
GCV, PCV and heritability were high for grain Zn for the genotypes. Grain Zn showed
a significant positive correlation with panicle length, grains per panicle and spikelet
fertility. Highest grain Zn was recorded in the environment which had relatively high
initial soil Zn and was then further added with fertilizer Zn while the lowest grain Zn
was recorded in the environment which had low initial soil Zn and no further Zn was
added with Zn fertilizer. However, increase in grain Zn with the addition of fertilizer Zn
was not uniform across the tested genotypes. The genotypes - Shraboni, Dehangi,
Kopouguni, Laishanka and Negilai recorded high grain Zn content across all the
environments. Inglongkiri, Panimudi, Arpang and Ranga Ahu showed good grain Zn
content in low Zn environment while Begungutia, Kolong, Disang and Ikhajoy showed
good grain Zn content in high Zn environment. The results suggest the possibility of
identifying high Zn genotypes and also the possibility of agronomic biofortification as
most of the genotypes showed increase in grain Zn with addition of external Zn to soil.
The genotypes exhibited significant variation in the individual environments as well as
over environments for most of the characters studied including yield and grain Fe.
Based on D2 analyses the genotypes were grouped in 5 different clusters of which 4
were mono-genotypic and the rest one was with 26 genotypes. Significant variation
among the genotypes as well as tested environments was also reflected in the stability
analysis. Shraboni, Dikhow and Rangadaria for grain yield and Shraboni, Dehangi,
Kopouguni, Laishanka and Negilai for grain Zn showed high mean performance with
average stability. There is significant variation among the crosses both in low and high
Zn environments for almost all the characters. Significant positive GCA effects were
found for grain yield and grain Zn for Inglongkiri and Kolong in both high and low Zn
environments. Heterosis over mid parent was seen for grain Zn in Kasalath×Inglongkiri
and for grain yield in Kasalath×Ikhojoy and Ikhajoy×Kolong. Heterobeltiosis was
recorded for grain Zn in Kasalath×Kolong in high Zn environment.