| dc.description.abstract | Brachiaria is a new forage grass that has been introduced in Kenya and other nations with a
big potential of enhancing the productivity of livestock. Its small seed size is however a major
limitation to mass adoption. Pasture production in Western Kenya is facing the pathological
and physiological issues which are caused by the Biotic and abiotic stressors and this poses
negative impact on the performance of livestock more so in dairy industry. Although its use
has gained increased significant, little information is available on the tolerance of the disease,
seed viability and agronomic performance of Brachiaria cultivars in dissimilar agro-ecological
settings, particularly its LM1 (Alupe) and LM2(Kakamega) cultivars. The current research
was prompted by this research gap, as well as growing need to find a sustainable substitute to
Napier grass. The overall aim of the research was to compare levels of disease incidence,
growth and yielding potential of some Brachiaria cultivars in some ecological areas of
Western Region, Kenya. In addition, the study had the objectives of assessing the disease
tolerance, growth performance, light interception, leaf area index (LAI), and yield potential of
selected Brachiaria cultivars Xaraes (Brachiaria brizantha cv. Xaraes), Piata ( Brachiaria
brizantha cv. Piata), MG4 (Brachiaria brizantha ), Basilisk (Brachiaria decumbens), and
Mulatto II (Brachiaria ruziziensis) with Mulatto II being used as a control. The split-plot
design was adopted, where cultivars were the primary plot factor and defoliation regime (no
defoliation, single defoliation, and constant defoliation since week 12) was the subplot factor.
Three repetitions of the experiment were done at two agro-ecological sites, namely KALRO
Kakamega (LM2) and KALRO Alupe, Busia (LM1), which were housed in a factorial design
of 3x5x2. Planting material was in form of root splits obtained in KALRO Kakamega. At the
planting stage, phosphate fertilizer, (40 kg/ha P2O5) was applied and nitrogen topdressed at
the rate of 100 kg/ha N. Data was recorded after every four weeks and involved plant height,
number of tillers, biomass yield, incidence of pest and disease, number of infloescences, seed
yield, and germination rates. Mulatto II grew to the highest and Basilisk the lowest in LM1;
the same occurred in the reverse in LM2. Basilisk had the most number of tillers in both
regions. False smut (58%), and ergot (69.33) had the greatest impact in LM2 on Basilisk.
MG4 had the lowest ergot incidence rate (41%), and Xaraes had the lowest false smut
incidence rate (32%). LM1 showed no cases of disease. Most cultivars intercepted more light
in LM2 than in LM1. The maximum interception of light penetration was higher in Mulatto II
with the lowest light interception in Xaraes in LM1. Basilisk was the light interception leader
in LM2, and Xaraes was the lowest. The same trend was observed with LAI, with exception
of MG4 which registered the lowest LAI in LM1. All cultivars had the potential to high
forage yield. Basilisk was the most profitable in LM1 and Piata was the least. In LM2 this
trend was inverted. The cultivars were also divided according to flowering time Basilisk,
MG4, and Mulatto II were early flowering and Xaraes and Piata were late flowering. Cultivar
had no significant effect on seed weight with Xaraes and Mulatto II recording the highest seed
weights at 100 seeds (0.38 +- 0.019 g) with Basilisk recording the lowest (0.32 +- 0.019 g).
But the germination of the seeds failed and fungus of a dark sooty soil appeared probably an
outcome of contamination with disease. The importance of the findings is that cultivars such
as MG4 and Basilisk have been identified having high forage yield, improved disease
resistance, and early flowering characteristics which are useful in breeding, pasture
enhancement, and sustainable seed production plans in Kenya. The findings are particularly
useful to small-scale dairy farmers, researchers, extension workers, and seed producers in
search of resilient, high-yielding forages to fit the local aspect of the environment. The
present study gives the background data of the performances of the specific Brachiaria
cultivars and outlines disease as a significant factor that reduces seed viability. Cultivar
specific disease response, defoliation response and light-use efficiency were created and can
inform future breeding programs and pasture management practices. The results enhance the
comprehension on improving the quality and availability of Brachiaria seeds, hence the use of
the results to support the process of upscaling Brachiara production and increasing the yield
of dairy in smallholder agricultural systems in Kenya. | en_US |
