Expression of the limited-transpiration trait under high vapour pressure deficit in peanut populations: Runner and virginia types

Drought can be a critical limitation on peanut yield. A physiological trait that may help to ameliorate drought is limited transpiration (TRlim), defined as a limitation on further increases in transpiration rate (TR) under high vapour pressure deficit (VPD) conditions. The advantage of the TRlim trait is that it allows plant water conservation to increase soil water availability for use during late-season drought. While this trait has been identified in peanut, there is no information of how readily the trait may be transfer to progeny lines. The objective of this study was to obtain preliminary information on the expression of the TRlim trait in two peanut progeny populations. One population was runner type of 88 RILs derived from the mating of Tifrunner x NC 3033. The second set was selected for the virginia-type phenotype of large pods obtained from mating of PI 585005 (ICGV 86015) and N0808olJCT, both of which expressed the TRlim trait. A two-tier screen was applied to both populations. The initial screen was based on exposure of de-rooted shoots to silver ions. Fifteen runner type and 12 virginia type were selected for direct measures of transpiration response to varying VPD. The results from each of the two populations showed that an effective expression of the TRlim trait occurred in about 30% of the progeny in each population. While these results do not offer a definitive index of inheritance, they do indicate that there appears to be a strong possibility of transferring the TRlim trait to progeny genotypes.