Stability of soil plant analytical development (SPAD) chlorophyll meter reading (SCMR) and specific leaf area (SLA) and their association across varying soil moisture stress conditions in groundnut (Arachis hypogaea L.) uri icon

abstract

  • The complex nature of physiologicaltraits associated with drought tolerance and thedifficulties associated with their measurements insegregating populations and large number of genotypesinhibited their use in the past in developingwater-use efficient genotypes in breeding programmes.With new knowledge of easily measurablesurrogates of transpiration efficiency (TE), atrait associated with drought tolerance?specific leafarea (SLA) and soil plant analytical development(SPAD) chlorophyll meter reading (SCMR), it isnow possible to integrate TE through the surrogatesin breeding and selection schemes in groundnut(Arachis hypogaea L.). As a noninvasive surrogate ofTE, SCMR is easy to operate, reliable, fairly stableand low cost. However, in a large-scale breedingprogram, it is difficult to complete SCMR observationswithin a specified time. The present studyaddressed the issue as to what extent the SCMRmeasurements can be spread over time by evaluating18 diverse groundnut genotypes for two physiologicaltraits, SCMR and SLA in two postrainy (Nov?Apr)seasons (2002/2003 and 2003/2004) in India. Observationswere recorded at different times during andafter the release of moisture deficit stress. There wasgeneral agreement in genotype and trait performancein both the seasons. Interaction between SCMR andtime of observation was significant in only one season(2002/2003) but its variance relative to genotypes andtime of observation was very small. ICGV 99029 andICR 48, which recorded higher SCMR and lowerSLA values in both the seasons, will make goodparents for water-use efficiency trait in breedingprogrammes. Other good parents include ICGS 76,TCGS 647 and TCGP 6. SCMR recorded at threedifferent times under differing soil moisture deficit ineach season showed highly significant correlationwith each other. Similarly, SLA at different timesalso correlated significantly with each other. SCMRand SLA were significantly negatively correlatedwith each other and the relationship was insensitiveto time of observation. The results of the presentstudy indicated that SCMR/SLA observations can berecorded at any time after 60 days of crop growth,preferably under moisture deficit conditions. Thisgives groundnut breeders a large flexibility to recordthese observations in a large number of segregatingpopulations and breeding lines in the field. Thus,making it easy to incorporate these physiologicaltraits associated with drought tolerance in breedingand selection scheme in groundnut

publication date

  • 2008
  • 2008