Physiological efficiencies in mini-core peanut germplasm accessions during summer season

Abstract

In the present study, the physiological efficiencies of 181 mini-core peanut accessions (genotypes) were evaluated according to variability in their physiological performance in the field during summer (2012). Genotypes were categorized into groups of high, medium, and low physiological activity. Thirty-four genotypes showed high net photosynthetic rate (P N > 33 μmol m-2 s-1), 28 genotypes exhibited high stomatal conductance (g s > 0.54 mmol m-2 s-1), 33 genotypes manifested high transpiration rate (E > 11.8 mmol m-2 s-1), 30 genotypes performed with high water-use efficiency (WUE > 3.8), 30 genotypes reached high chlorophyll SPAD values (SCMR > 40), and 35 genotypes showed high maximum quantum yield of PSII (Fv/Fm > 0.86). In addition, few genotypes showed high values for multiple physiological traits. A total of 54 genotypes exhibited higher values in two, 20 genotypes showed a high value in three, and in eight genotypes, high values occurred in four different physiological traits. Interestingly, only two genotypes, NRCG 14493 and 14507, showed high values for five different traits. Positive correlation was observed between g s and P N, E, and g s, and between P N and Fv/Fm, while WUE and E showed a negative correlation. The genotypes with high P N, g s, and WUE coupled with high SCMR and Fv/Fm could be used in peanut crop improvement programme for yield enhancement as well as stress tolerance.