Volume 1 Number 1 July 2015

Relationship between Tobacco Crop Evapotranspiration and the Normalized Difference Vegetation Index

Authors: Never Mujere ; Rudo Kanji
Pages: 9-14
Monitoring crop consumptive water use by applying recent remote sensing techniques has become a topic of research interest in water resources management and planning.  In irrigated agriculture, conventional methods of estimating water use are costly.  This study aims at estimate the relationship between tobacco crop evapotranspiration (ETcrop) and the normalized difference vegetation index (NDVI) during the crop development stage at Chedgelow irrigated farm in Zimbabwe. Tobacco ETcrop was estimated as a product of reference evapotranspiration (ETo) and crop coefficient (Kc). The Penman-Monteith model was applied to estimate ETo using climate data from Kutsaga research station, some 2 km away from the farm. Kc values were extracted from FAO tables. Five cloud-free MODIS images for the month of October in 2000, 2001, 2002, 2003 and 2007 were processed extract the NDVI values using ILWIS GIS. The results show significant (p = 0.000) differences between tobacco NDVI values over the years studied. The results also show a strong and significant positive relationship (r2 = 0.8061, p = 0.047) between ETcrop estimated using Penman Monteith model and NDVI. Research findings show that satellite derived NDVI is a good and reliable predictor of tobacco crop water evapotranspiration. Therefore, remotely sensed NDVI can be used to monitor crop water use in irrigated tobacco fields in areas where resources do not permit field measurements.

Evaluation of Heterosis in Pearl Millet (Pennisetum Glaucum (L.) R. Br) for Agronomic Traits and Resistance to Downy Mildew (Sclerospora Graminicola)

Authors: Ati Hassana Maryam
Pages: 1-8
An experiment was carried out in Bakura and Zaria to evaluate heterosis for downy mildew resistance in some pearl millet using Complete Randomized Block Design. Four resistant varieties (PEO5532, SOSATC88, P1449 and DMR15) and four susceptible varieties (BDP1, MOP1, LCIC9702 and PEO5984 were used as male and female respectively. The resistant varieties were crossed with the susceptible varieties using North Carolina design 11. Sixteen (F1) hybrids obtained were evaluated along with their parents for downy mildew resistance, grain yield and other agronomic traits. The analysis of variance showed highly significant difference among parents and hybrids for all agronomic characters. Location × genotype interaction effects were only significant for grain yield and number of panicles per plot. The study selected the best parents that give high heterosis in terms of yield components, yield and downy mildew resistance. Two hybrids PEO5984 × P1449 and PEO5984 × PEO5532 had significant heterosis for 50% days to flower ng, PEO5984 × P1449, PEO5984 × PEO5532, PEO5984 × DMR15 and PEO5984 × SOSATC88 for yield, the best MP and BP heterosis for downy mildew incidence is PEO5984 × P1449 and MOP1 × p1449 for MP heterosis and BDP1 × P1449 for BP heterosis. Correlation among the characters studied showed that magnitudes of genetic correlation were higher than those of phenotypic correlation in some of the traits considered. The number of panicles / plot and panicle weight / plot showed significant genetic correlations indicate degree of correlation with grain yield. This showed that selection for any of these characters could lead to indirect selection of grain yield.