VIABILITY OF RUBBER TREE SEEDS AS A FUNCTION OF STORAGE TIME

Abstract

THE RUBBER TREE SEEDS HAVE A HIGH RATE OF PERISHABILITY BECAUSE THEY ARE RECALCITRANT, WHICH MAKES IT DIFFICULT TO STORE THEM. IN ADDITION, THE SEED VIABILITY TEST USUALLY OCCURS BY SEEDLING EMERGENCE TEST, WHICH VARIES FROM 10 TO 30 DAYS, DURING WHICH TIME THE VIABILITY OF THE SEED MAY FALL SIGNIFICANTLY. THUS, THE USE OF RAPID TESTS THAT VERIFY THE VIABILITY OF THE SEEDS BEFORE PLANTING IS ESSENTIAL TO PROVIDE INFORMATION ABOUT THEIR GERMINATIVE POWER. AMONG THEM, WE CAN MENTION THE ELECTRICAL CONDUCTIVITY, MOISTURE AND TETRAZOLIUM TEST. THE OBJECTIVE OF THIS STUDY WAS TO ANALYZE THE VIABILITY OF RUBBER TREE SEEDS OF RRIM600 CLONE AS A FUNCTION OF STORAGE TIME. FOUR THOUSAND RUBBER SEEDS WERE COLLECTED FROM THE RRIM 600 CLONE, WHICH WERE PLACED IN PLASTIC BAGS, SEALED AND STORED AT ROOM TEMPERATURE (�± 26 �° C). THE TESTS (EMERGENCE OF SEEDLINGS IN SAND BEDS, TETRAZOLIUM, MOISTURE, ELECTRICAL CONDUCTIVITY) WERE PERFORMED ON THE DAY OF COLLECTION AND THEN AT 30, 60 AND 90 DAYS AFTER STORAGE. THE EXPERIMENT WAS CONDUCTED IN A COMPLETELY RANDOMIZED DESIGN WITH FOUR TREATMENTS (STORED FOR 30, 60 AND 90 DAYS) AND FOUR REPLICATES. THERE WERE NO SIGNIFICANT DIFFERENCES BETWEEN THE MEAN PERCENTAGE OF SEEDLING EMERGENCE TEST IN THE FIELD AND THE GERMINATION ESTIMATE OF THE TETRAZOLIUM TEST. THERE WAS A POSITIVE CORRELATION BETWEEN THE PERCENTAGE OF GERMINATION AND THE ESTIMATE OBTAINED BY THE TETRAZOLIUM TEST OVER THE STORAGE PERIOD, NEGATIVE CORRELATION BETWEEN SEEDLING EMERGENCE PERCENTAGE AND MOISTURE CONTENT AND ELECTRICAL CONDUCTIVITY. THE REGRESSION ANALYSIS OF THE EMERGENCE PERCENTAGE OF RUBBER TREE SEEDLINGS AS A FUNCTION OF STORAGE TIME GENERATED A QUADRATIC MODEL WITH SIGNIFICANT R2 VALUES �€‹�€‹AT 5% PROBABILITY. REGARDING THE MOISTURE CONTENT AS A FUNCTION OF STORAGE TIME, A LINEAR MODEL WAS OBTAINED, WITH R2 SIGNIFICANT AT 5% PROBABILITY. THUS, IT CAN BE CONCLUDED THAT THE TETRAZOLIUM TEST CAN BE USED IN PLACE OF THE EMERGENCE TEST OF SEEDLINGS IN RUBBER SEEDLINGS. THE TETRAZOLIUM, MOISTURE, AND ELECTRICAL CONDUCTIVITY TESTS ARE EFFICIENT AND RAPID TESTS IN THE EXECUTION. RUBBER SEEDS CAN BE STORED VIABLE AT ROOM TEMPERATURE (24-28 �° C) FOR UP TO 2 MONTHS. THE MOISTURE CONTENT OF APPROXIMATELY 25% WAS THE MOST EFFICIENT FOR THE CONSERVATION OF THE RUBBER TREE SEEDS.