The study evaluated the performance of new inbred rice varieties applied with seaweed extracts as sources of plant growth regulators (PGRs) in the lowland ecosystem of Nueva Vizcaya. The set-up was conducted at a farmer's field located in Brgy. Uddiawan, Solano, Nueva Vizcaya from August 5, 2023 to November 13, 2023. Split-plot was used in three replications. The treatments consisted of two factors: The Main Plot (Variety) were V1-NSIC Re 508, V2-NSIC Re 512 and V3 - NSIC Re 514 and Sub-plot (Fertilizer) was F1-Farmers Practice, F2-100-30-30 kg NPK per hectare (General Recommendation for Irrigated Rice), F3 - Farmers Practice + Seaweed Extract (4 liters per hectare) and F4-100-30-30 kg NPK per hectare (General Recommendation for Irrigated Rice) + Seaweed Extract (4 liters per hectare).

There was no significant difference between the new rice varieties (NSIC Re 508, NSIC Rc 512, and NSIC Rc 514) in terms of flag leaf, leaf blade length, number of productive and unproductive tillers, number of filed spikelets, or weight of 1000 grains. Along with similar Chlorophyl Content Index (CCI) values, they also had comparable mean values for infestation by leaf folder and stemborer and infection of bacterial leaf blight. Conversely, NSIC Rc 508 was similar in height to NSIC Re 512 but noticeably taller than NSIC Re 514. Compared to the other two types, NSIC Re 512's flag leaf and leaf blade were noticeably wider. The three types were similar to one other. The three varieties had comparable numbers of productive and unproductive tillers, filled spikelets, 1000-grain weight, and yield per hectare. Compared to the other two varieties, NSIC Re 508 produced the longest panicles, the fewest unfilled grains, and the heaviest dry grain weight. Regardless of variety, the addition of seaweed extract had no significant effect on growth parameters except plant height. In this parameter, adding seaweed to Farmers Practice (F3) resulted in the tallest plant height, which was significantly different from the application of the recommended fertilizer rate alone. The addition of seaweed extract to the Recommended Rate of Inorganic Fertilizer (RRIF) based on Soil Analysis (F4) of fertilizer application increased yield significantly, regardless of variety. In this application, the highest values were obtained in the number of productive tillers, length of panicles, number of filled spikelets, weight of 1000 and dry grains, and yield per hectare were significantly different from the rest of the fertilizer treatments.

The interaction between variety and fertilizer affected the number of unproductive tillers and chlorophyll content at 27 DAT but did not affect the height of plants at maturity. length and width of flag leaf, length of the leaf blade, number of productive, length of panicles, number of filled and unfilled spikelets per panicle, the weight of 1000 grains dry grain weight per sampling area, grain yield per hectare, the infestation of bacterial leaf blight at 57, 63 and 70 DAT, the infestation of leaf folder at 57, 63 and 70 DAT and infestation of stemborer at 70 and 77 DAT, chlorophyll content at 27 and 40 DAT and chlorophyll content at 69 DAT. The interaction of NSIC Re 508 variety x Recommended Rate of Inorganic Fertilizer (RRIF) based on Soil Analysis + Seaweed extract obtained the highest Return on Expenses with 179.99 percent and a yield of 9.13 metric tons per hectare.. 

Thesis (Master of Science in Crop Science - Agronomy)

Includes appendices and bibliographical references