Understanding the shattering process: differences on seeds shattered at different times in Panicum coloratum var. makarikariense

M. MAINA; M.A. TOMAS; L.V. ARMANDO

Pergamino

Congreso; 9° Congreso Internacional de Semillas Forrajeras y Céspedes; 2017

Panicum coloratum var. makarikariense is a warm-seasonperennial grass potentially used as forage on heavy clay soils with lowdrainage. Due to non-uniform development of thepanicle and low seed retention, poor quality and quantity of seed are usually harvested. We aim evaluatingwhether there is a change in weight and germination in seeds shattered atdifferent times. We conducted an experiment comparing seeds shattered at 2 and4 weeks after anthesis. We further studied the relationship of morphologicalcharacters of the mother plant with seed traits. Fifteen spaced-plants from 13 half-sib families in a complete randomizedblock design with 5 replications were measured at INTA EEA Rafaela (31°11?41?? S;61°29?55?? W) totalizing 195 plants. Shattered seeds were harvest weekly fortwo months from a specially designed seed trap. Seed retention (SR) wasestimated as the relative number of seeds retained over the total seed number by panicle (SN). We focused on seedsshattered 15 (2) and 30 (4) days after anthesis. At these dates, seed weight (mg, SW2 and SW4) and germinationpercentage (%, PG2 and PG4) of seeds were evaluated. Number of panicles by plant (PN), flag leaf area (cm2, FLA) and number of leaves per panicle (LN) were also measured. Variability amongfamilies was analyzed by ANOVA. Differences on average PG and SW at eachharvest date were compared by the t student test. Results showed that familiessignificantly (p<0.01) differed in SW2, SW4, PG4, SN, SR4 and PN. No significant differences were detected for PG2, SR2, LN y FLA.Additionally, both PG and SW were significantly (0<0.01) higher at the 2ndharvest than at the 4th one. Correlations between variables werealways low (r<0.20); only some were significant (positive for SN-PG4 andLN-FLA); and negative for SN-PN, SN-PR4 and PN-PG4). Differences in seedscharacteristics among families as well as differences between seeds shatteredat different times should be further studied to increaseunderstanding of the shattering process.