Dynamic analysis of pecan(Carya illinoensis 'Pawnee') nut development

【Objective】To elucidate dynamic change and quality mechanism of pecan nut development.【Methods】Morphology changes such as fruit weight,nut weight,fruit length,nut length,fruit width,nut width,fruit shape index,nut shape index,kernel weight,kernel percentage,peel thickness andshell thickness of pecan(‘Pawnee') were measured and analyzed.【Results】The results indicated thatfruit weight,kernel weight,kernel percentage,fruit length,nut length,fruit width,nut width,nutshape index showed a first increase and then decrease pattern; Peel thickness increased and fruit shape in-dex decreased gradually,shell thickness first decreased and then increased during nut development.【Conclusion】During 145-155 d after full blossom,most traits especially key traits which determine thenut quality and marketability reached the optimum value. Nuts should be harvested in time to prevent thequality decline. Variation of most traits showed a significant positive correlation with each other and hadbind effects mutually.