Genomic microsatellite markers are capable of revealing high degree of polymorphism. Sugarcane (Saccharum sp.), having a complex polyploid genome requires more number of such informative markers for various applications in genetics and breeding. With the objective of generating a large set of microsatellite markers designated as Sugarcane Enriched Genomic MicroSatellite (SEGMS), 6,318 clones from genomic libraries of two hybrid sugarcane cultivars enriched with 18 different microsatellite repeat-motifs were sequenced to generate 4.16 Mb high-quality sequences. Microsatellites were identified in 1,261 of the 5,742 non-redundant clones that accounted for 22% enrichment of the libraries. Retro-transposon association was observed for 23.1% of the identified microsatellites. The utility of the microsatellite containing genomic sequences were demonstrated by higher primer designing potential (90%) and PCR amplification efficiency (87.4%). A total of 1,315 markers including 567 class I microsatellite markers were designed and placed in the public domain for unrestricted use. The level of polymorphism detected by these markers among sugarcane species, genera, and varieties was 88.6%, while cross-transferability rate was 93.2% within Saccharum complex and 25% to cereals. Cloning and sequencing of size variant amplicons revealed that the variation in the number of repeat-units was the main source of SEGMS fragment length polymorphism. High level of polymorphism and wide range of genetic diversity (0.16-0.82 with an average of 0.44) assayed with the SEGMS markers suggested their usefulness in various genotyping applications in sugarcane.

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Family selection is widely used in early stages of selection in sugarcane breeding programs. Families are evaluated in the first one or two stages of selection and individual clones are selected from within superior families. These selected clones are evaluated for their performance in two or three selection stages before commercial release of superior clones. This study was undertaken to assess the relative performance of five sugarcane families for predicting potential parental combinations and also to identify rare and elite recombinants that can be exploited in future. Results from this study highlighted that two families viz., Co 7704 x Co 8209 and Co 85002 x Co 86011 contributed a greater proportion of elite clones combining acceptable levels of cane yield and sugar yield. The top ten clones selected based on sugar yield from the stage II evaluation holds greater promise in the subsequent regional selection programs. Overall, the findings suggest that selection of the best families based on their mean performance and further selection of individual clones based on their sugar yield in early stages would improve the efficiency of selection and increase heritability in the genetic populations being tested.

Collection HIGHLIGHTS Sugarcane hybrids with improved IWUE have greater scope in sugarcane agriculture as irrigation water is getting scarce.  Among sugarcane hybrids, Co 8371 registered high mean water productivity of 4.18 kg m -3 , followed by Co 85019(3.92 kg m -3 ), while in I 2 , six hybrids had significantly higher water productivity (Co 85019, Co 0212, Co 86249, Co 10026, Co 0218 and Co V92102) above 4 kg m -3 .  Deficit irrigation scheduling (irrigation at recommended interval, with 50% crop evapotranspiration replacement) appears to be far more useful than reducing frequency as well as quantity of irrigation water alone. Hybrid mean water productivity was 3.2, 2.7, and 2.1 kg m -3 in I 0 , I 1 , and I 2 , respectively.ABSTRACT. The escalating deficit rainfall scenario in India indicates that drought is a recurrent phenomenon associated with tropical sugarcane farming, and the availability of irrigation water for sugarcane cultivation will be much less in coming years. To meet the challenge of limited and costly water supply, tropical sugarcane growers will have to find ways of increasing the efficiency of irrigation to maintain high cane yields. More efficient irrigation systems, accurate irrigation scheduling, and the right choice of sugarcane hybrids are potential means of increasing irrigation water use efficiency (IWUE), water productivity (WP), and global water security. With the objective of optimizing irrigation water use, a field experiment evaluating the physiological efficiency of commercial sugarcane hybrids for WP in a sandy clay soil under water-limited conditions was conducted during 2016-2017 at the ICAR-Sugarcane Breeding Institute in Coimbatore, India. The replicated field experiment was laid out in split-plot design with three irrigation levels as the main plot and 33 sugarcane hybrids as subplots. The prevailing climatic conditions during the experiment represented a tropical wet and dry climate, with the wet season lasting from October to December due to the northeast monsoon. The results showed that full irrigation at recommended intervals with 100% crop evapotranspiration (ET) replacement (I 0 ) produced significantly higher cane yield than deficit irrigation at recommended intervals with 50% crop ET replacement (I 1 ) and skipping alternate irrigations with 50% crop ET replacement (I 2 ). The deficit irrigation treatments (I 1 and I 2 ) had declines in cane yield of 41.2% and 56.4%, respectively. IWUE was similar in I 0 and I 1 , while I 2 had reduced IWUE by 23%. WP was significantly influenced by irrigation level; reduction in irrigation water reduced WP by 17.5% and 36.3% in I 1 and I 2 compared to I 0 . Among sugarcane hybrids, Co 85019, Co 13006, Co 10026, Co 99004, CoLk 8102, Co 86249, Co 8371, Co 94008, and Co 95020 yielded higher than the genotypic mean under both deficit irrigation treatments, suggesting their usefulness in deficit irrigation strategies. Sugarcane hybrids with high WP can play a pivotal role in sustaining sugarcane productivity and can reduce the larg...