LEAF AREA ESTIMATION IN SUNFLOWER AND CAPITULAM DIAMETER– SEED YIELD REGRESSION

Abstract

To estimate sunflower (Helianthus annuus L.)plant leaf area in a simple and quick formula , the maximum width of one whorl was multiplied by a constant and compared to a convential formula.. A field experiment was conuducted at the Dept. of Field Crop Sci./Coll.of Agric. of the Univ.of Baghdad in spring season of 2013. Two cultivars of sunflower were planted , the non-oil Shumoos and the oil Akmar .At anthesis , plant leaf area were estimated on a sample of each cultivar. The correlation coefficient was determined between plant leaf area and each whorl leaf area. The correlation was highly significant between whorl five in Shumoos cv. and whorl six in Akmar cv. ( r=0.857** and 0.863**, respectively) Regression relationship between capitulam seed yield and diameter was tested.The new formula to estimate plant leaf area in non- oil was = 4.04∑wi^2 w 5 and for oil cultivar 4.31∑wi^2 w6.The wi^= width of whorl 5 leaves (from the top ) and w5 and w6 are the numbers of whorls .The leaf area measurements were in a good fit up to ∝ =0.99 according to t-test analysis meanwhile, correlation and regression between capitulam seed yield and diameter were analyzed. The correlation coefficients were highly significant (r= 0.817** and 0.795** for non-oil and oil cvs., respectively) . The estimated seed yield and the observed were similar up to probability of 0.99 according to t-test analysis . The formula for non-oil cv. was: Y= -99 + 10.14 X and for oil cv. : Y=-99.9 + 8.42 X .The symbol Y= seed yield (gms) and (x) is the capitulum diameter (cm). It was concluded that these four formulae were very simple, accurate, and quick. We recommend using them in the field by sunflower researchers.