Fruit growth and development of Sijimi longan and its mathematical model

ObjectiveThe present experiment was conducted to investigate fruit growth and development of off-season Sijimi longan, in order to provide a theoretical basis for taking appropriate measures to improve yield and quality of Sijimi longan fruits. MethodTaking Sijimi longan as materials, the fruit growth and development indexes including longitudinal diameter, large transverse diameter, small transverse diameter, single fruit fresh weight, pericarp weight, pulp weight, seed weight, soluble solids content were determined. The mathematical models of fruit growth and accumulative rate were established by polynomial regression and derivation calculus methods. ResultThe fruit growth of off-season Sijimi longan took 108 d, fruit mature stage lasted 21 d. The fruit diameter increased slowly at early stage, and rose fast to the peak at middle stage, then increase gently. The pulp weight, pericarp weight, seed weight and single fruit weight began to in-crease rapidly on 52 d after flowering, the soluble solids content began to increase rapidly in 66-94 d after flowering, then reached to the peak(25.1%). Based on to data about fruit indexes of Sijimi longan, the mathematical model of fruit growth was established, the multiple regression equations were obtained by fitting curve, including quadratic equations for longitudinal diameter, transverse diameter, fruit weight and pulp weight, cubic equations for pericarp weight, seed weight and soluble solids content. The results of F-test showed that, significant differences were found in regression equations of dynamic model(P<0.05), and the determination coefficients(R2) were above 0.9800, indicating that there existed ex-tremely significant difference(P<0.01). Furthermore, the models for accumulative rates of longitudinal diameter, trans-verse diameter, single fruit weight and pulp weight of Sijimi longan fruit were linear equations, the models for accumula-tive rates of pericarp weight, seed weight and soluble solids content were quadratic equations. ConclusionThe dynamic and mathematical models for growth and development of Sijimi longan fruit can provide reference for formulating high-yield and high-quality cultivation and management measures.