Effect of chemical sprays and management practices on Brachiaria ruziziensis seed production

- Irrigation and fertiliser application improved amount of pure seed production in Brachiaria ruziziensis.
- The quality of Brachiaria ruziziensis seeds depends mainly on harvesting method.
- Brassinosteroid 10% and Tryptophan 100% could improve the seed yield in Brachiaria ruziziensis.
- Treating the seeds with raw cow dung and other beneficial microorganisms improve the field germination in Brachiaria ruziziensis.
- Replanting the sward every year is suggested for the Brachiaria ruziziensis seed production.

The demand for Brachiaria ruziziensis seeds and planting material is increasing in India as it is spreading into new niche areas of silvi-pastoral systems, horti-pastoral systems, mango orchards, and coconut plantations due to its resilience to drought and low light intensities. Brachiaria ruziziensis produces low numbers of pure seeds. In this study, seeds were collected periodically after a single destructive harvest (SDH) and shade drying. Application of irrigation and fertiliser produced a 2.3 fold increase in seed yield compared to the control. However, when seeds were collected through a single destructive harvest (SDH) and shade drying, rather than sweating, the seed qualitative parameters such as seed germination and seed viability improved three and five folds, respectively. Field management techniques such as irrigation and fertiliser application influenced the quantity of seeds produced whereas harvesting methods promoted the quality of seeds produced in B. ruziziensis. Seed germination could also be improved (50%) by treating the seeds with raw cow dung which contains many beneficial microorganisms that produce cellulolytic enzymes, alleviating seed dormancy. Seed yield improved in B.ruziziensis with chemical sprays such as Brassinosteroid 10 ppm (145 kg/ha) and Tryptophan 100 ppm (147 kg/ha) compared to the control, water spray (131 kg/ha). Brassinosteroid sprays could enhance pollen fertility and yield probably through interactions with anther development and sugar metabolism, respectively. Brachiaria ruziziensis produces more vegetative growth in the second year due to its perennial growth habit. The filled seed yield from the second-year crop was 0.8 times less in the control compared to the first year, even with chemical sprays. Perennial plants, in general, maintain their longevity through a physiological trade-off between seed yield and underground growth. Hence, it is beneficial to replant B. ruziziensis every year if grown for seed purposes.