Influence of Cone Physical Characteristics and Extraction Exposure Period on Seed Yield of Pinus patula

Abstract

This study examines the correlation between extraction exposure periods and cone physical characteristics on Pinus patula seed yield. Systematic random sampling was employed for tree identification in an even-aged clonal seed orchard, and the laboratory phase was laid down as a factorial experiment with two factors: cone physical characteristics and extraction exposure period at three levels. Seed counts were taken for cones categorized as; heavy, light, narrow, and wide at three extraction exposure periods 6 hours, 12 hours, and 24 hours in a constant oven temperature of 65°C. The experiment had 12 (L1,H1,N1,W1,L2,H2,N2,W2,L3,H3,N3,W3)treatments with 60 cones per treatment. The time spent counting and returning cones during the inter-stage observation ranged from 10 to 15 minutes. Data collected were tabulated and means analyzed using ANOVA with results generated as per the objectives. The number of seeds released within the hours of exposure was captured as the seed extraction rate. The first six hours yielded the optimum number of seeds per cone with the mean highest number of seeds from wide cones. The lowest mean number of seeds released observed was 28, from light cones, while the highest mean number of seeds was observed to be 56 from wide cones. Cone sorting based on size before extraction is recommended for optimized seed yield. The stages of seed extraction employed here can be used in mechanized seed extraction cabinets equipped with timers at controlled temperatures.