Drought yield index to select high yielding rice lines under different drought stress severities

Abstract

BackgroundDrought is the most severe abiotic stress reducing rice yield in rainfed drought prone ecosystems. Variation in intensity and severity of drought from season to season and place to place requires cultivation of rice varieties with different level of drought tolerance in different areas. Multi environment evaluation of breeding lines helps breeder to identify appropriate genotypes for areas prone to similar level of drought stress. From a set of 129 advanced rice (Oryza sativa L.) breeding lines evaluated under rainfed drought-prone situations at three locations in eastern India from 2005 to 2007, a subset of 39 genotypes that were tested for two or more years was selected to develop a drought yield index (DYI) and mean yield index (MYI) based on yield under irrigated, moderate and severe reproductive-stage drought stress to help breeders select appropriate genotypes for different environments.ResultsARB 8 and IR55419-04 recorded the highest drought yield index (DYI) and are identified as the best drought-tolerant lines. The proposed DYI provides a more effective assessment as it is calculated after accounting for a significant genotype x stress-level interaction across environments. For rainfed areas with variable frequency of drought occurrence, Mean yield index (MYI) along with deviation in performance of genotypes from currently cultivated popular varieties in all situations helps to select genotypes with a superior performance across irrigated, moderate and severe reproductive-stage drought situations. IR74371-70-1-1 and DGI 75 are the two genotypes identified to have shown a superior performance over IR64 and MTU1010 under all situations.ConclusionFor highly drought-prone areas, a combination of DYI with deviation in performance of genotypes under irrigated situations can enable breeders to select genotypes with no reduction in yield under favorable environments compared with currently cultivated varieties. For rainfed areas with variable frequency of drought stress, use of MYI together with deviation in performance of genotypes under different situations as compared to presently cultivated varieties will help breeders to select genotypes with superior performance under all situations.

Efficiency of drought tolerance indices under different stress severities for bread wheat selection

“…These relationships became less strong at 0.57 compared to 0.25 and 0.35 stress intensities. These results were reported by Mohammadi et al (2011);; Raman et al (2012) and Rahmani et al (2013). SNPI had also strong correlation with Ys at 0.25 stress intensity (below 90°); however, the overlap of vectors was observed at 0.35 and 0.57 stress levels.…”

“…Regarding Fernandez groups selection (1992) at 20 % selection pressure, the same indices (MP, MSTIk1, Pi, MSTIk2, MRP, REI, GMP, STI, HARM and RDY) selected efficiently the group A at 0.25 except MSTIk1 which integrated one genotype from group B to its list of selection. Many studies have reported the effectiveness of these indices in selecting high yielding and drought tolerant genotypes (Rosielle and Hamblin, 1981;Fernandez, 1992;Ramirez and Kelly, 1998;Hohls, 2001;Golabadi et al, 2006;Jafari et al, 2009;Talebi et al, 2009;Mohammadi et al, 2010;Raman et al, 2012). However, the drought indices are influenced by stress intensity and difference in drought patterns among locations and years.…”

“…Many studies (e.g. Moosavi et al, 2008;Talebi et al, 2009;Mohammadi et al, 2010;Mohammadi et al, 2011;Farshadfar and Elyasi, 2012;Raman et al, 2012;Golinezhad et al, 2014) have highlighted the efficiency of the indices for drought tolerance selection. However, none of these studies had treated all the major indices listed in the literature to establish the relationships between them and avoid the redundancy of their use.…”

Marker-assisted breeding to develop the drought-tolerant version of Sabitri, a popular variety from Nepal

“…Drought yield index (DYI) was calculated using the formula described by Raman et al (2012) as follows:…”

Challenges of Integrated Water Resources Management in Indonesia

“…Drought can change its characteristics through time [22] and mainly affects the second crop of irrigated and rain-fed rice fields, normally these rice fields have two rice cropping seasons, the first is a period from November to February and the second is that from March to June for each year [23]. Annually about a total of 0.250 million hectares, approximately 3% of the total planted rice fields, of the second crop of rice fields is affected by drought.…”