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Broadening genetic base through backcross breeding is an effective approach to generate diverse genetic stocks for important economic traits coupled with red rot resistance. Three hundred backcross hybrids developed by backcrossing elite F1 clones (derived by utilizing improved clones (S.officinarum, S. robustum and S. barberi) with improved S. off...
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... days were from improved S. officinarum x improved S. robustum crosses. The clone 13-69 with the highest sucrose of 20.26% at 12 months of age is from the cross combination of (PIO 03-107 x PIR 96-475) x PIO 03-107. The BC 1 hybrids 13-69, 13-103 and 13-251 showed an improvement of 4.54, 2.63 and 2.79% for quality: juice sucrose % at 360 days ( Fig. 2) and more recombinants with high mean brix was obtained with improved S. officinarum as one of the parent in backcrosses. Among the BC 2 clones 14 -42 recorded the highest sucrose of 22.71% followed by 14-66 (21.86%), and 14-161 (21.06%) at 360 days in comparison with Co 86032 (19.03%). The clones, 14-76, 14-69, 14-163 and 14-174 ...
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... These clones are utilized by sugarcane breeders in India to improve commercial varieties. Alarmelu et al. (2018) reported two-backcross hybrids viz.14-57 and 14-60 with S. barberi cytoplasm for further utilization. ...
... Intra-population improved YLD free population improved S. officinarum (PIO) and population improved S. robustum (PIR) clones were identified for use in in the interspecific hybridization (Karuppaiyan et al. 2020). Alarmelu et al. (2018) identified a high sucrose BC derivatives (1-69) from the PIO x PIR cross with sucrose content of 20.26% at 12m. ...
This chapter describe inter-specific and inter-generic hybridization in sugarcane. The success and failure of wide hybridization in Saccharum, inter-generic hybrids produced, cytological behavior in inter-generic hybrids etc are also dealt.
Sugarcane is an economically important crop, and the impact of climate change can be manifested much more in all stages like germination, tillering, grand growth, and maturity phases. Cane yield and sucrose content are the two principal traits determining commercial cane yield of sugarcane genotypes. Sucrose accumulation in sugarcane stalks is known as ripening, which is influenced by ambient air temperature and sheath moisture index of sugarcane genotypes. Early ripening genotypes are photosynthetically efficient and complete the vegetative developmental phase much faster than the mid-late cultivars by their synchronized tillering phase and low ratio of acid and neutral invertases. Prolonged lower air temperature during the maturity phase before harvest favors sucrose synthesis in sugarcane genotypes due to decreased concentration of acid invertase enzymes in stalks. The average daily temperature of 12–14 °C would be more desirable for proper ripening. However, a drastic decline in temperature below 8 °C during ripening alters the activities of sucrose synthesizing and hydrolyzing enzymes resulting in a sharp decline in sugar recovery. The impact of changing temperature regimes on sucrose accumulation emphasizes future research initiatives to develop improved models that can record the crop physiological processes that will simulate crop response to predicted changes in climate. Modeling approaches predicted that increased sucrose yield could be achieved when the decrease in stalk dry mass is not more than 10%. Impact assessment using CANEGRO model to study the effect of various combinations of temperature and CO2 projected an enhance in fresh stalk biomass and a decrease in sucrose mass by nearly 10–70% (rainfed) and 6–37% (irrigated) in 2040–2060 compared to 1971–2000 across the agro-climatic areas in India. Therefore, detailed studies are required in the future to demonstrate the causes of changes in the behavior of commercial varieties and the effect of climatic variables on the enzyme balance that regulates vegetative growth and ripening.
Thirty-one sugarcane genotypes were planted in the experiment and post-emergence application of Halosulfuron Methyl 75% WG and Metribuzin 70% WP was carried out at the rate of 67.5 g and 1000 g a.i. per hectare on 42 days after planting (DAP). Lower leaves of some of the genotypes were found to show injuries on 5 days after spraying (DAS). Phytotoxicity was recorded in visual scoring scale of 0 to 10 at 7, 15, 21 and 30 DAS. Phytotoxicity rating of the 31 genotypes studied ranged between 0 and 4. Nine genotypes showed no visual injury and found tolerant, while eight genotypes showed moderate toxic effect (rating 4). All the genotypes (14 nos.) that showed phytotoxicity rating of 1 to 3 recovered visually (leaf injuries) except Co 06027 at 30 DAS, while all the genotypes that showed moderate phytotoxicity did not recover completely except Co 94008. The genotypes with Co 7201 and Co 775 as one of the parents showed phytotoxicity rating ranging from 1 to 4. The genotypes, Co 06030, Co 86032, Co 11015, Co 92005 and Co 09004 did not exhibit phytotoxicity symptoms, while their parent, CoC 671 exhibited phytotoxicity. Seven parental genotypes showed 100% probability of no herbicidal injury in their progenies and exhibited herbicidal tolerance from initial stage. Cane yield reduction (> 5%) was observed only in Co 8021, Co 94008 and Co 99006 with herbicide treatment over no herbicide application. The present study provides a preliminary information on the genetic variation among sugarcane genotypes for herbicide tolerance and their parental relationship, which could be utilized for the development of herbicide tolerant varieties for effective weed management in sugarcane agriculture.
