
%0 Journal Article
%A Hubick, KT 
%A Shorter, R 
%A Farquhar, GD 
%T Heritability and Genotype &#215; Environment Interactions of Carbon Isotope Discrimination and Transpiration Efficiency in Peanut (<I>Arachis hypogaea</I> L.)
%J Functional Plant Biology
%D 1988/12/01
%V 15
%N 6
%P 799-813
%K 
%R https://doi.org/10.1071/PP9880799
%U https://www.publish.csiro.au/paper/PP9880799 
%X The discrimination, &#916;, against 13C in carbon accumulation by different genotypes of peanut was investigated by looking at changes in composition of isotopes of CO2 during CO2 assimilation and at the 13C/12C ratio in dry matter. The short term (minutes) discrimination, which was measured as CO2 passed over leaves in a gas exchange cuvette, was positively related to pi/pa, the ratio of the pressure of CO2 inside the leaves to the pressure of CO2 around the leaves, which is independently related to transpiration efficiency, W. Heritability of &#916; was studied in plants grown in pots and in the field. Crosses were made of cultivars with contrasting &#916; and W. For these genotypes, small &#916; (and large W) seemed to be dominant in the F1 progeny. Severe drought stress slightly decreased &#916; and W in F2 plants but, for parental genotypes in another experiment, &#916; decreased but W increased when they were less severely stressed. A strong negative phenotypic correlation (r = -0.78) was found between W (g DM/ kg water used) and &#916; in the leaves of well-watered potted plants of F2 progeny from a cross between two cultivars with contrasting W and &#916;. Transpiration efficiency varied significantly among cultivars of peanut irrespective of whether plants were drought-stressed or well-watered. Transpiration efficiency in the potted F2 plants had a heritability of 34% while &#916; had a heritability of 53%. The broad sense heritability of &#916; in fieid-grown cultivars was 81% and there was no significant genotype &#215; environment interaction for &#916;. The high heritability of &#916; and its strong genetic correlation with W indicates that &#916; is a suitable selection criterion for W in peanut breeding programs. 
