Comparison of Response to Nitrogen between Upland NERICAs and ITA (Oryza sativa) Rice Varieties

Abstract

Average yields of upland rice are the lowest in Uganda, and most of the productivity gains attributed to improved varieties are related to increased area of production from clearing virgin lands for rice production. In a bid to optimize productivity, we compared the effect of four nitrogen fertilizer treatments: 0, 40, 80 and 120 kgN/ha and two variety types (ITAs (Oryza sativa) and NERICAs (New rice for Africa)) on grain yield and yield parameters in four locations. Combined analysis of variance revealed that nitrogen fertilizer increased mean grain yields from 2116-5200 kg/ha in the NERICAs and 2331-5100 kg/ha in the ITAs. In all the study areas, NERICA 4 and NARIC 2 outperformed NARIC 1 and NERICA 1, and yield trends were consistent over the years suggesting that the two varieties respond better to N fertilizer application. However, the productivity gains are probably related to genetic potential of the varieties rather than the N fertilizer effect, as reflected by the consistent relative performance between 0 N and other N rates. The heavier grains of NARIC 2 and NERICA 4 suggest greater dry matter accumulation before heading, as these varieties have a longer period of vegetative growth. The significant interaction of location x fertilizer and location x variety reveals the need for evaluating the nitrogen-supplying power of soils in the various cropping systems in the country.

Influence of rice varieties and fertility levels on performance of rice and soil nutrient status under aerobic conditions

“…Higher 1000-grain weight was recorded in PR-121 as compared to other varieties which may be due to ability of this cultivar to partition dry matter towards seeds. These results corroborate the findings of Onaga et al (2012). Similarly, Kastura and Nakaide (2011) found that the rice varieties with greater sink capacity and source activity per plant could produce heavier grain weight under aerobic conditions.…”

Drought-induced root plasticity of two upland NERICA varieties under conditions with contrasting soil depth characteristics

“…For instance, in western Kenya (Atera et al, 2011) and multiple locations in Tanzania (Sekiya et al, 2013), NERICA 1 had a higher yield than NERICA 4. On the other hand, farmers in the semi-arid Kerio Valley of Kenya (Kinyumu, 2009), multiple locations in Uganda (Onaga et al, 2012), and parts of northern Nigeria (Kamara et al, 2010) selected NERICA 4 because of its higher yields than NERICA 1. The inconsistencies in yield performance of NERICA 1 and NERICA 4, which have been observed even under the same climatic conditions, could be due to the differences between the two varieties in drought avoidance mechanisms and their expression in different soil environments.…”

Productivity and Economic Performance of NERICA Varieties under Two Harvest Modes and Rainfall Intensities in Uganda

“…Matsumoto et al [24], recorded higher yields of NERICA 1 and NERICA 4 (5,501kg ) under lower rainfall. Onaga et al [23], reported no significant differences in the grain filling ratio of NERICA and NARIC varieties with similar traits given different N levels. NERICA 6 produced higher grain yield at 90 DAE when the 65% panicles had matured.…”

“…Peltonen et al [22], observed tiller development and stem leaf growth to positively correlate with incident solar radiation. Onaga et al [23], reported significantly higher number of tillers and panicles for NERICA 1 and NERICA 4 under increased application of N fertilizers.…”

“…This may be a genetic characteristic for the cultivars. Onaga et al [23], reported higher spikelets per panicle under NERICA 4 than NERICA 1 and attributed the observations to higher nitrogen use efficiency coupled with genetic potential of NERICA 4. The higher percent filled panicles and grain yield recorded under NERICA 1, NAMCHE 2 and NERICA 4 relative to NERICA 6 at 75 DAE may be attributed to higher uptake of water and nutrients and tolerance to water stress at the meiosis-anthesis and panicle initiation stages, since the three varieties are early maturing.…”