Title: Variation of in vitro dry matter digestibility in Brachiaria ruziziensis populations

Biography:

Sarayut Thaikua studied Biology at Ramkhamheang University, Thailand and graduated as BS in 1996. In 2005, he studied Plant breeding at Khonkaen University, Thailand and graduated as MS in 2009. After that he got the scholarship from Royal Thai government for Ph.D., and he received his Ph.D. in Science of Bioresource Production (Pasture Science) at Kagoshima University, Japan in 2015, with supervised by Prof.Yasuhiro Kawamoto. Then he returned to Thailand, and he has been worked at Bureau of Animal Nutrition Development, Department of Livestock Development in Thailand focusing on forage crop breeding.

Abstract

In vitro dry matter digestibility (IVDMD) is the important character for tropical forage, Brachiaria improvement (Thaikua et al. 2015), and phenotypic recurrent selection is the effective practical method in breeding for increased IVDMD in open-pollinated forage crops (Burson and Young 2001), The available variance within breeding population is the indicator of the possibility of the successful improvement.   Ten genotypes of diploid B. ruziziensis (Thai population) and 10 genotypes of tetraploid ‘Okinawa-1’ (Ishigaki et. al. 2009) were evaluated in completely randomized design with 2 replications. Each genotype was clonal propagated by stolon with roots, and grew in 20 cmx20cm culture plastic pot containing sand, with 8 cm depth. Plants was supplied by water every day, and enriched fluid nutrient (21-21-21) were applied once a week. All plants were cut for adjustment at 1 month after planting. The average shoots of each plant were collected at 5 weeks after the cut. Each sample was oven dried at 65°C for 48 hours, and ground to pass through a 0.5 mm mesh screen. Pepsin-cellulase method was utilized for IVDMD determination. Analysis of variances showed the significant difference of IVDMD within both populations, with the P-value less than 0.0001 for diploid population and 0.0471 for tetraploid group. In vitro dry matter digestibility means with homogeneous group (Tukey test) of the first population was 77.5 A, 76.5 AB, 76.2 ABC, 76.0 ABCD, 75.0 BCDE, 74.6 CDE, 74.4 DE, 74.0 E, 73.8 E, and 72.0 F, while that of the second population was 77.6 A, 75.0 AB, 74.9 AB, 74.4 AB, 73.6 AB, 73.4 AB, 72.4 AB, 72.2 AB, 71.6 AB, 70.9 B. However, there was no significant different on IVDMD between 2 populations (P=0.0966). This study revealed that it is possible in population improvement for increased IVDMD in both populations.