The Physiological Basis of the Genetic Progress in Yield Potential of CIMMYT Spring Wheat Cultivars from 1966 to 2009

By K. Aisawi, Matthew P Reynolds, R. Singh, M. J. Foulkes. 2015

214 citations recorded by the source corpus.

our objective was to investigate the physiological basis of genetic progress in grain yield in CIMMYT spring wheat ( Triticum aestivum L.) cultivars developed from 1966 to 2009 in irrigated, high-potential conditions. Field experiments were conducted during three growing seasons in northwest Mexico (2008–2009, 2009–2010, and 2010–2011) examining 12 historic CIMMYT semidwarf spring wheat cultivars released from 1966 to 2009. The linear rate of genetic gain in grain yield was 30 kg ha −1 yr −1 (0.59% yr −1 ; R 2 = 0.58, P = 0.01). Grain yield progress was associated with increased aboveground dry matter (AGDM) at harvest ( R 2 = 0.80, P < 0.001) and heavier grain weight ( R 2 = 0.46, P < 0.05). There was a positive linear association between AGDM and plant height ( R 2 = 0.43, P < 0.05) and between grain weight and the date of complete canopy senescence (CCS) among the 12 cultivars ( R 2 = 0.36, P < 0.05). There was no change in grains per square meter or harvest index (HI) with year of release (Yor). Grain weight was positively associated with potential grain weight (pGW), and pGW, in turn, was positively associated with rachis length per spikelet among the cultivars. overall spike dry matter (DM) per square meter at anthesis (GS61) +7 d did not change with Yor. There was a trend for a linear increase in AGDM of fertile shoots (expressed as g m −2 ) at GS61 +7 d with Yor, but this was counteracted by spike partitioning decreasing overall during the 43-yr period from 0.25 to 0.23. There was a linear increase in preanthesis flag-leaf stomatal conductance with Yor ( P < 0.05). There was no change in grain growth response to a degraining treatment imposed at GS61 +14 d (mean grain weight response +5.5%) indicating that the degree of source limitation to grain growth appeared to be small and unchanged in the older and modern cultivars. Generally, these results indicated that the rate of genetic progress in CIMMYT spring wheat has slowed but has not plateaued in recent decades, while genetic gains were associated with increase in both potential and final grain weight. degrees of freedom, when the ANOVA indicated significant differences. For ANOVAs across years, Bartlett’s test ( P = 0.05) was used to test for the homoge-neity of variances, and years were regarded as random effects. The mean square for the year effect was tested against an error A mean square representing the variation between blocks. The mean square of the cultivar and year effects was tested against an error B mean square representing residual variation. Treatment means were compared using the LSD.

Subfields: Agronomy and Crop Science, Plant Science

View Paper: https://www.semanticscholar.org/paper/9749583be488d33c7499337c326ee2f9206500a7

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Agronomy and Crop Science

In Plant Science

Citations in the corpus

Genetic Progress in Grain Yield and Physiological Traits in Chinese Wheat Cultivars of Southern Yellow and Huai Valley since 1950 (2017, background): “Although little genetic change in aboveground biomass (AGBM) was observed in some studies (Tian et al., 2011; Zheng et al., 2011; Sanchez-Garcia et al., 2013), significant genetic change was reported in others (Donmez et al., 2001; Shearman et al., 2005; Xiao et al., 2012; Aisawi et al., 2015).”
Strategic crossing of biomass and harvest index—source and sink—achieves genetic gains in wheat (2017, background): “The idea that biomass contributes to yield is borne out by theory—a large biomass pushes the theoretical yield margin—and in practice, since biomass is commonly associated with genetic gains in yield (Aisawi et al. 2015).”
Avoiding lodging in irrigated spring wheat. I. Stem and root structural requirements (2016, background): “…be recognised that the500 breeding program at CIMMYT has increased the plant height of wheat to 1.0 m or above in the period of501 1966 to 2009 (Aisawi et al. 2015), where the raised bed planting system may favour taller crops better at502 capturing the light in the gaps between the beds early…”