J. Agronomy & Crop Science 175. 83—86 (1995) © 1995 Blackwell Wissenschafts - Verlag, Berlin ISSN 0931-2250 Department of Crop Physiology and Project Co-ordinating Unit (Sunflower), University of Agricultural Sciences, GKVK, Bangalore 560 065, India An Improved Non-destructive Method for Rapid Estimation of Leaf Area in Sunflower Genotypes Y. A. NANJA REDDY, M. N . KESHAVA MURTHY, K. VIRUPAKSHAPPA and R. UMA SHAANKER Authors' addresses: Dr Y. A. NANJA REDDV, M. N . KESHAVA MURTHY and Dr. R. UMA SHAANKF.R (corresponding author). Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bangalore 560 065, India; Dr. K. VlRUPAKSHAPPA, Project Co-ordinating Unit (Sunflower), University of Agricultural Sciences, CKVK, Bangalore 560 065, India With 2 figures and I table Received October 24, 1994; accepted January 5, 1995 Abstract Measurement of total leaf area per plant in crop improvement programmes for a variety of purposes is often very tedious and time consuming. In this paper, we offer a rapid and non-destructive method of estimating the total leaf area in sunflower at the time of anthesis. We show that multiplying the leaf area of a specific leaf position from the apex by the total number of leaves per plant yields total leaf area with more than 95 7o accuracy. The specific leaf position for any given genotype in sunflower can be arrived at by multiplying the total number of leaves per plant by the factor 0.355 and rounding off to the nearest highest integer. This technique can be used for the rapid estimation of leaf area per plant at anthesis for any given genotype of sunflower. Key words: Actual leaf area, estimated leaf area, relative leaf position, sunflower. Introduction In recent years, sunflower {Helianthus anmms L.) has become an increasingly important edible oil seed crop in many countries of the world. However, as in several other crops, the pro- ductivity of sunflower is constrained by poor light interception due to generally low leaf area index (ROLLIER 1982). In this context, increas- ing emphasis is being laid on screening and exploiting the existing genetic variability for leaf area and to incorporate them in breeding programmes. A practical problem beset with such screening is, however, the issue of esti- mating the total leaf area per plant. Measure- ment of total leaf area in situ by the conventional technique (length X breadth x 0.69; SCHNEITER 1978) is tedious and man- power oriented. Recently, PALAKONDA REDDY et al. (1991) proposed a rapid technique for estimating the total leaf area ot plant by measuring the leaf area of a specific leaf position and substituting it in the equation Y = 628 + 0.514 n\, where 'x' is the leaf area of the specific leaf (for instance 8th leaf) and 'n' is total number of leaves per plant. This method yields estimates of leaf area with more than 90 % accuracy. However, a disadvantage of this technique is that it cannot be generalised over genotypes, because the specific leaf posi- tion giving the smallest deviation of the esti- mated leaf area from the actual total leaf area varies with genotypes. This constrains the use of the technique in estimating the leaf area of any given genotype. In this paper we develop an alternate tech- nique tor estimating the total leaf area oi sun- flower irrespective of genotype. This technique IS non-destructive, rapid and yields estimates of leaf area with more than 95 % accuracy. U.S. Copyright Clearance Center Code Statement: 0 9 3 1 -2250 /95 /7502-0083$l 1. 00 /O