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Flooding is one of the major constraints for rice production in rainfed lowlands, especially in years and areas of high rainfall. Incorporating the Sub1 (Submergence1) gene into high yielding popular varieties has proven to be the most feasible approach to sustain rice production in submergence-prone areas. Introgression of this QTL into popular varieties has resulted in considerable improvement in yield after flooding. However, its impact under non-flooded conditions or years have not been thoroughly evaluated which is important for the farmers to accept and adopt any new version of their popular varieties. The present study was carried out to evaluate the effect of Sub1 on grain yield of rice in different genetic backgrounds, under non-submergence conditions, over years and locations. The study was carried out using head to head trials in farmer’s fields, which enable the farmers to more accurately compare the performance of Sub1 varieties with their recurrent parents under own management. The data generated from different head to head trials revealed that the grain yield of Sub1 varieties was either statistically similar or higher than their non-Sub1 counterparts under non-submergence conditions. Thus, Sub1 rice varieties show no instance of yield penalty of the introgressed gene.

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Invasive weeds degrade ecosystems and are a threat to plant and animal biodiversity. The literature on biological invasions suggests that only 10% of introduced species become invasive in a new host range. Most introduced plants do not become invasive in a new environment. The invasive behavior of a weed depends on the weed's genetic variability, biotic factors, and climatic factors with which it interacts. The climatic factors that affect the invasive traits of weeds include the atmospheric temperature, soil temperature, precipitation, evaporation, and CO2 concentration. The biological traits that are influenced by a change in any one or more of these climatic factors include the pattern of assimilate partitioning, induction of dormancy or seed germination, herbivore tolerance, propagule production and distribution, variability of plant architecture, photosynthetic rate, and seedbank longevity. The impact of climate change on the invasive traits of certain weed species is reviewed.