[P1] Field Crop Production

[P1-27] Leaf Senescence Evaluation of Selected Interspecific Progenies between O. sativa and O. glaberrima; NERICA Varieties for Stay-Green Characteristics during Grain-Filling Period

*Nominated for Presentation Awards

^○Peter Balyejusa Ssenyonga¹, Shin Yabuta², Shotaro Tamaru³, Jun-Ichi Sakagami^1,2,3 (1.Graduate School of Agriculture, Forestry and Fisheries, Kagoshima University, Japan, 2.Faculty of Agriculture, Kagoshima University, Japan, 3.The United graduate School of Agricultural Sciences, Kagoshima University, Japan)

The stay-green ability in rice plants is an important factor for plant survival in especially stressful environments. The characteristic has shown potential function for additional dry matter production in some cereal varieties. Leaf greenness directly impact leaf activity in terms of photosynthesis performance main source of energy for plant organs growth. In this experiment, we evaluated the leaf chlorophyll content (SPAD) in flag leaf sections under incubation conditions to ascertain varietal senescence performance differences during the grain-filling period for stay-green characterization. In the glasshouse six NERICAs (1, 4, 10, 19, 41 and 60) varieties were grown and were evaluated from heading, 20 days and 40 days after flowering (DAH). The flag leaf, a center section of 5 cm length was incubated in dark at 35⁰C and daily SPAD reading was recorded. There was a drastic decline in the SPAD value of the flag leaf of NERICA 19 and 41, followed by NERICA 60 in the glasshouse. The period SPAD value reduced by 50% (T₅₀); NERICA 1 and 10 at 20 DAH was superior with 6.7 and 5.1 days longer, respectively. NERICA 1 and 4 at 40 DAH scored higher with 4.9 and 3.1 days, respectively compared to other varieties. NERICA 1 and 4 showed a strong negative correlation between flag leaf SPAD value of plant and section incubation at both 20 and 40 DAH. The preliminary findings suggest NERICA 1 to be a candidate variety for stay-green characterization due to prolonged leaf senescence with further physiological growth and environmental assessments.