EFFECT OF FARMING PRACTICES AND FARM HISTORY ON INCIDENCE OF COCONUT LETHAL YELLOWING IN MOZAMBIQUE

Management of coconut ( Cocos nucifera ) lethal yellowing disease (CLYD), which has killed about eight million coconut trees in Mozambique, has proved challenging. The objective of this study was to investigate the impact of farming practices and related history, on the CLYD incidence in Mozambique. The methodology included a socioeconomic questionnaire to the households and direct observations on the palm farms. The collected data were analysed using logistic regression. Five out of 11 explanatory variables tested, namely farm age, availability of other palm species on the coconut farm, type of coconut varieties grown, root cut practices, and intercropping had a significant (P< 0.05) effect on CLYD incidence. Coconut farms <10 years had higher odds of higher disease incidence compared to the farms between 10 to 40 years old. The presence of other palm species in the coconut farms had two times higher odds of having higher disease incidence levels compared to farms without other palm species. Tall coconut varieties were likely to be more tolerant to CLYD compared to dwarf varieties. Coconut farms with some kind of intercropping had two times higher odds of having higher disease incidence levels compared to pure stands. The practice of cutting coconut roots had three times higher odds of having high disease incidence levels compared to non-practicing farms. Farm age, availability of other palm species on the coconut farm, type of coconut varieties grown, root cut practices and intercropping need to be considered for integrated CLYD management.

RESPONSE OF LOCALLY ADAPTED PEARL MILLET POPULATIONS TO S1 PROGENY RECURRENT SELECTION FOR GRAIN YIELD AND RESISTANCE TO RUST

In the semi-arid zones of Uganda, pearl millet ( Pennisetum glaucum (L.) R. Br.) is mainly grown for food and income; but rust (Puccinia substriata var indica (L.) R. Br.) is the main foliar constraint lowering yield. The objective of the study was to genetically improve grain yield and rust resistance of two locally adapted populations (Lam and Omoda), through two cycles of modified phenotypic S1 progeny recurrent selection. Treatments included three cycles of two locally adapted pearl millet populations, evaluated at three locations. Significant net genetic gain for grain yield (72 and 36%) were achieved in Lam and Omoda populations, respectively. This led to grain yield of 1,047 from 611 kg ha-1 in Lam population and 943 from 693 kg ha-1 in Omoda population. Significant improvement in rust resistance was achieved in the two populations, with a net genetic gain of -55 and -71% in Lam and Omoda populations, respectively. Rust severity reduced from 30 to 14% in Lam population and from 57 to 17% in Omoda population. Net positive genetic gains of 68 and 8% were also achieved for 1000-grain weight in Lam and Omoda, respectively. Traits with a net negative genetic gain in both populations were days to 50% flowering, days to 50% anthesis, days to 50% physiological maturity, flower-anthesis interval, plant height and leaf area.