Optimization of germination and initial quality of seedlings of Prunus persica tree rootstocks

Abstract: The present study evaluated the germination potential of seeds from eight peach tree rootstocks under different stratification methods, aiming at the production of high quality seedlings. In the first experiment, seeds with endocarp from eight genotypes (‘Aldrighi’, ‘Capdeboscq’, ‘Flordaguard’, ‘Okinawa’, ‘Okinawa roxo’, ‘Tsukuba 1’, ‘Tsukuba 2’, ‘Tsukuba 3’) were stratified on sand and moist vermiculite, at 7 ºC for 60 days. In the second experiment, endocarpless seeds of the same genotypes were stratified on Petri dishes at 7 ºC. In the third experiment, the time at which at least 75% of the seedlings reached transplanting height (15 cm high) was verified. The endocarp was a limiting factor for seed germination of the eight rootstocks, since the highest germination percentages were 21% and 48.3% for ‘Aldrighi’ and ‘Capdeboscq’, respectively. Germination of ‘Okinawa’ was only 19.2% and 4.2%, in sand and vermiculite, respectively. Seeds stratified without the endocarp, showed 100% germination, except for ‘Flordaguard’ and ‘Tsukuba 2’ and 3’, with 93% germination. Seed mass presented a positive correlation with the germination speed index and the initial growth of the seedlings. ‘Aldrighi’ and ‘Capdeboscq’ presented more vigorous seedlings with greater growth in height, stem diameter, and Dickson quality index.