Abstract:In order to understand the changes in amino acid contents of pigeonpea (Cajanus cajan) leaves, the amino acid contents from 19 pigeonpea germplasms at 1-3-leaf-old were determined. The results showed that there were 17 kinds of amino acids in leaves of all pigeonpea germplasms at different leaf ages. The contents of threonine, isoleucine and lysine were the highest among the essential amino acids, with amounting to 0.67%, 0.70% and 0.48%, respectively, while those of serine, tyrosine and histidine were the highest among non-essential amino acids, with amounting to 0.69%, 0.66% and 0.44%, respectively. Except lysine and alanine, the other 15 kinds of amino acids in the leaves of pigeonpea generally increased along leaf age. The contents of total amino acids in the leaves were significantly different among different pigeonpea germplasms. Nineteen pigeonpea germplasms could be divided into four types by cluster analysis, such as low amino acid type (I), medium amino acid type (Ⅱ), medium and high amino acid type (Ⅲ) and high amino acid type (IV). Therefore, these would provide a theoretical basis for the processing of high-quality leaf tea and breeding of high-amino acid varieties of pigeonpea.