Genetic Gain in Yield and Associated Changes in Agronomic Traits in Wheat Cultivars Developed Between 1900 and 2016 for Irrigated Ecosystems of Northwestern Plain Zone of India

Abstract

Knowledge about the yield gain over the years due to associated changes in the yield component traits is essential for a critical understanding of yield-limiting factors. To estimate genetic gain in grain yield (GY) and component agronomic traits of wheat varieties released between 1900 and 2016 for northwestern plain zone (NWPZ) of India and to identify agronomic and/or genetic basis of the realized gains, two sets of wheat varieties comprising mega varieties and two recently developed varieties were evaluated under timely sown, tilled, and early sown conservation agriculture (CA) conditions for four consecutive years under irrigated conditions. The average annual genetic gain in GY since 1,905 under timely sown irrigated conditions was found to be 0.544% yr−1 over the average of all varieties and 0.822% yr−1 (24.27 kg ha−1 yr−1) over the first released variety, NP4. The realized mean yield increased from 2,950 kg ha−1 of the variety NP4 released in 1,905–5,649 kg ha−1 of HD3086 released in 2014. Regression analysis revealed a linear reduction in height and peduncle length (PL) over the years with a simultaneous and linear increase in biomass at the rate of 43.9 kg ha−1 yr−1 or relatively at 0.368% yr−1 mainly because of delayed heading and increased crop duration. Regression analysis showed no linear trend for tiller number and thousand-grain weight (TGW). Though harvest index (HI) was found to linearly increase relatively at the rate of 0.198% per annum, polynomial regression improved the fitness of data with the indication of no increase in HI since 1982. Interestingly, genetic gain evaluation under early sown CA conditions for 4 years showed similar relative gain (RG) [a relative improvement in varieties across breeding periods (BP)] (0.544% yr−1) but with a higher absolute value (29.28 kg ha−1 yr−1). Major mega varieties like Kalyan Sona, HD2009, PBW 343, HD2967, and HD3086, which occupied a comparatively larger area, were found highly plastic to the improvements in the production environment under timely sown conditions.

The performance of the genetic gain and breeding progress of historical winter wheat cultivars set in the period from 1930 to 2013 in South-eastern Europe

“…Application of these methods could enable an appropriate selection of stable cultivars in order to respond to the high year-to-year variable climate of the Pannonian Plain and South-eastern Europe. To determine a genetic gain achieved through breeding activities, experiments with historical cultivar sets were conducted (Yadav et al, 2021). Research like this has so far been done on a significantly smaller number of genotypes in a shorter time under the environments of South-eastern Europe.…”

Genome-wide association studies reveal putative QTLs for physiological traits under contrasting phosphorous conditions in wheat (Triticum aestivum L.)

“…Since then, yield gain rates are declining in many parts of the world (Yadav et al, 2010). In one of our recent assessments of varieties released over a century-long period (since 1905) for India's north-western plain zone, the wheat yield has grown at the rate of 0.544% (Yadav et al, 2021).…”

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“…Naturally, triticale line couldn't be at least 10% upper than the production of the Bezostaia 1 variety. Since the beginning of this century, genetic progress in wheat has slowed, which means that genetic variability has reached a maximum [1,14,3,8,11] the threshold that would could be overcome by improving the plant phenotype [2,5], due to increasing the crop growing season [17,6,12] more fertile flowers/spikelet, as well as a high availability of photosynthesis products [16,20,19,13].…”