Sugarcane Breeding for salt affected soils of subtropical India

Sugarcane important commercial crop of India. Both saline and sodic soils also contribute significantly in affecting cane yield and sugar recovery. In view of this, Effort was made to screen 32 genotypes of sugarcane of diverse genetic background against soil salinity at Nain farm, Panipat. (CSSRI, Karnal) during 2015-16. The soil salinity of the experimental area varies greatly from 2.25 dSm-1 to 29.04 dSm-1 at different crop intervals. Under this experiment, 9 entries were planted under various levels of electrical conductivity. Based on the performance of these entries, an experiment was planted for further evaluation at ICAR-SBI-RC, Karnal under four salinity level of irrigation waters viz., Normal, 4 EC.iw: 4 dSm-1, EC.iw: 8 dSm-1 and EC.iw: 12 dSm-1 Five clones were identified as tolerant and six clones were moderately tolerant whereas Six genotypes were found highly sensitive clones. These tolerant and moderately tolerant clones may be utilized in breeding programme towards development of salinity tolerant varieties.

Physiological Differential Response Of Sugar Cane (Saccharum Officinaruml.) On Water Deficit Condition

Sugarcane is the main sugar-producing plant in the world and also plays an important role as a raw material for bioethanol production. Productivity improvement of the plant is exposed to environmental stress ie: water shortage which is currently a serious problem associated with the global climate change phenomenon. Understanding of plant responses to environmental stress is one of the keys to be able to resolve the issue. In this regard, the fundamental studies related to the sugarcane plant responses to water stress is very important. This study consists of a combination of two factors, namely the type of clones consisting of PS.864, PSJT.941, and VMC.76-16, 851 as tolerant group clones, PS.862, PS.882 and PS.851as non tolerant clones group and lack of water stress treatment for 5 days. The data were analyzed further using DNMRT at 5% significance level. Observations showed that tolerant clones as well as non-tolerant clones PS.862 showed better resistance response than non tolerant groups. The indication was shown by the value of the Relative Water Content (RWC), Specific leaf area (SLA) and Water Deficit Value (WDV). Total protein profiling of sugarcane grown under water deficit and its counterpart differentially distinguished by suppression of protein expression of about 35 kDa in all clones. While in the water deficit condition expression of a protein with a size of 25 kDa is remarkable expressed.

Grafting influence on productivity and drought tolerance of tea clones

Grafting of fresh cuttings using drought-susceptible and low-yielding clones as scions on drought-tolerant clones as rootstocks offers the possibility of raising composite plants with improved productivity and drought tolerance. Hence, the study was aimed to widen the choice of compatible composites and to delineate the underlying factors responsible for productivity and drought tolerance in grafted plants. One year-old composite plants of TRF-1, TRF-2 and UPASI-28 cleft-grafted on the rootstocks of UPASI-2, UPASI-9, ATK-1 and TRI-2025 were field planted along with their respective controls and evaluated. The results indicated that productivity and drought tolerance of scion clones varied significantly with the rootstocks used. Significant increases in yield and yield components were noted in the following graft combinations compared with their corresponding self-rooted scion clones: TRF-1 grafted on UPASI-9 and ATK-1, TRF-2 grafted on all four rootstocks, and UPASI-28 grafted on UPASI-9, TRI-2025 and UPASI-2. The findings clearly emphasize the scion–rootstock interaction as the critical determinant of productivity in grafted plants compared with vigour, drought tolerance and yield potential of scion and rootstock clones. Further, high-yielding capacity of grafts over the ungrafted scions and rootstocks was largely dependent on the yield potential of the scion clone and the degree of scion–rootstock compatibility. Higher field survival and enhanced yield observed during the drought period in the compatible grafts demonstrated their better drought tolerance compared with their respective self-rooted scions.

Evaluation of tea clones for resistance/tolerance to mites infestations and the influence of environmental factors on mites dynamics in Kenyan tea farms

Mites infestations reduce yields in tea production world wide. However, some tea cultivars are resistant/tolerant to mites attack. The resistance/susceptibility can also be influenced by abiotic factors. This study evaluated some new tea clones for mite resistance/susceptibility and influence of Environmental factors (weather parameters) on dynamics of mite infestations of Kenyan tea at different ecological zones, Kangaita, Kipkebe and Timbilil. Maximum population of mites was reported during March when maximum temperature, average rainfall and relative humidity ranges for the sites were 23.9-28.7°C, 27.7-50.1mm and 38.0-70.4% respectively. There was a sharp decline in mites population in April when average rainfall was high (398.4-514.4mm) which was accompanied by reduction in maximum temperature (18.8-27.5°C) and increase in relative humidity (44.0-82.2%). The minimum population density was found during August which was characterized by low maximum temperature (16.4-26.6°C), low average rainfall (4.8- 190.5mm) and high average relative humidity (46.0-80.9%). The mites infestation levels highly correlated with maximum temperatures in Kangaita (r² = 0.801), Kipkebe (r² = 0.693) and Timbilil (r² = 0.744). There were significant (p≤0.05) monthly variations in clonal mite infestations at all sites. Susceptible clones showed higher monthly mite infestations variations than the resistant/tolerant clones. Of the clones evaluated for the first time, eight new clones were identified as tolerant/resistant while two clones were susceptible to mites attack. Resistant/tolerant clones are recommended for commercial exploitation while mitigation strategies should be put in place in mites prone areas during hot seasons with high monthly temperatures and low humidity