Cane Diameter Research Articles

Response of 2A Clone grape to GA3 sprays for berry thinning as influenced by cane regulation on two training systems under tropical conditions

With an aim to minimize manual thinning in 2A Clone of ‘Thompson Seedless’ grapevine trained on bower and extended Y trellis and grafted on “Dogridge” rootstock, investigations were carried out in growers’ vineyards around Nashik, Maharashtra during 2013–14. Gibberellic acid (GA3) was sprayed at 10 ppm thrice or 15 ppm twice. Since the response to GA3 for berry thinning is stage specific, attempts were made to induce uniform bud break by retaining the canes of uniform diameter, consequently achieve uniformity in the stage of panicles that is ideal for GA3 sprays. Efficacy of GA3 sprays in reducing the cluster compactness on different training systems (bower or extended Y trellis) and with cane regulation was assessed. Less cane diameter but more uniform bud break was observed on extended Y trellis and cane regulated vines. Uniformity in the stage of panicle was not influenced by either the training system or cane regulation. Clusters were less compact in spite of the larger berries on Y trellis with two sprays of GA3 @ 15 ppm. Although this combination was highly effective in reducing the cluster compactness, clusters in all the treatments were in the range of loose to wellfilled. Cane regulation coupled with two sprays of GA3 @ 15 ppm or retention of all canes coupled with three sprays @ 10 ppm resulted in more yield. These interactions were more pronounced on bower. Total soluble solids content and berry specific gravity were more on extended Y trellis while the titratable acids content was less on this trellis in cane-regulated vines. Taking cluster compactness, yield and quality into consideration, two sprays of GA3 at 15 ppm on extended Y trellis but three sprays @ 10 ppm on bower, with or without cane regulation were found best.

Influence of Rootstocks on Growth Yield and Fruit Composition of Thompson Seedless Grapes Grown in the Pune Region of India

The use of rootstocks is gaining importance in Indian viticulture due to problems associated with abiotic stresses, such as drought and salinity, and also to improve scion characteristics. Thompson Seedless is the only commercial cultivar grown for both fresh consumption and raisin making. Dog Ridge was the only popular rootstock used by grape growers prior to late 1990s. But this rootstock was known to induce more vigour in scions, resulting in reduced bud fruitfulness and thereby fruit yield. To identify alternate rootstocks suitable for Thompson Seedless, a study was initiated in the National Research Centre for Grapes, Pune, India during the year 2001. Five rootstocks with own rooted vines were evaluated in this study. During the initial years, Thompson Seedless grafted on Dog Ridge produced the highest yield, with good quality fruit. Over the years we could observe uneven bud sprouting, gaps on the cordon due to dead wood formation, and reduced yield in vines grafted on Dog Ridge rootstocks. In contrast, Thompson Seedless grafted on 110R performed well in terms of moderate vigour, increased fruitfulness and consistently higher yield. Dog Ridge and St. George produced a lower yield, owing to increased vigour measured in terms of pruning weight, total shoot length and cane diameter. Rootstocks 110R, 1103P and 99R are also known to increase water-use efficiency during critical growth stages of fruit bud differentiation and full bloom. No significant influence of rootstocks was observed for most of the fruit composition parameters. Larger and bolder berries were produced on Dog ridge and 110R rootstock, while they were the smallest on own rooted vines.

Biochemically Induced Variations During Some Phenological Stages in Thompson Seedless Grapevines Grafted on Different Rootstocks

Phenological variation in Thompson Seedless grapevines grafted on different rootstocks and own rooted vines was assessed for two consecutive years and the reasons for such variations were studied through biochemical analysis. Uniform and early bud sprouting was recorded in the vines grafted on 110R rootstock and on own roots, which was attributed to increased peroxidase activity and protein content in the buds before bud burst. Increased fruitfulness on 110R rootstock and own rooted vines was attributed to the increased phosphorus and protein content of those vines and reduced vegetative vigour measured in terms of shoot length, cane diameter and pruned biomass. Thompson Seedless grafted on Dogridge rootstock recorded the highest nitrogen content, increased shoot length, cane diameter and increased pruned biomass attributing to reduced fruitfulness. The highest concentration of phenolic compounds and amino acids was recorded in the fruits produced on 110R rootstock, while it was least on St. George and own roots. Significant variation in the accumulation pattern of amino acids (especially proline and arginine) was observed, with the least proline/arginine ratio recorded on 110R rootstocks at the time of harvest, indicating the variation in the days taken for fruit ripening on different rootstocks.

Enhancing Cane and Sugar Productivity and Profitability Through Relay Intercropping of Autumn Sugarcane with Skipped-Row-Planted Rice in Subtropical Climatic Conditions of India

The on-farm trials were conducted for two consecutive seasons of 2007–2009 and 2008–2010 using a participatory approach on cultivators’ fields at Bikamau village in Lucknow District of India’s central Uttar Pradesh to explore the feasibility of planting autumn sugarcane at 90-cm row spacing as a relay intercrop in every fifth skipped row of July-transplanted rice at 18-cm row spacing in late September and/or October for enhanced cane and sugar productivity in the Indian subtropics. The cropping system was compared with rice–spring sugarcane and rice–autumn sugarcane. The on-farm trial results revealed that germination (64.4 %) of cane buds, tillers (328,000/ha) and number (155,000/ha), length (225 cm), diameter (2.4 cm) and weight (752 g) of millable cane were markedly better when autumn sugarcane was planted as a relay intercrop in rice in comparison with other cropping systems. Similarly, this cropping system produced the maximum cane (123.4 t/ha) and sugar (14.51 t/ha) along with sugarcane equivalent yields (149.9 t/ha). In turn, relay intercropping system with maximum cane production efficiency of 291 kg/ha/day fetched the highest economic returns (Rs. 262/ha/day) and benefit-to-cost ratio (1.98). Comparing with rice–spring sugarcane cropping system, relay intercropping of autumn sugarcane in standing rice produced 33 and 35 % more cane and sugar yield, respectively, with 42 % higher returns besides 79 % energy saving. This practice may grossly benefit cane growers and sugar mill owners alike in the Indian subtropics, particularly in rice-growing and low-lying areas of eastern Uttar Pradesh and north Bihar.

Correlation and Path Coefficient Analyses in Sugarcane Genotypes of Ethiopia

To study the relations of certain morphological and sugar quality characters with sugarcane yield, an experiment was conducted at Wonji and Metehara Sugar Estates, Ethiopia between March 2012 and October 2013. The experiment, comprising of 400 sugarcane genotypes of which 174 were local that were collected from different regional states of Ethiopia and 226 introduced, was laid out in partial balanced lattice design with two replications. Data was collected on cane yield and its components, sugar yield and sugar quality traits. ANOVA, correlation and path coefficient analysis were done. Analysis of variance revealed significant differences (P (r = 0.832), single cane weight (r = 0.528), stalk height (r = 0.517) and sugar yield (r = 0.987). There was also positive significant (P = 0.05) correlation of tiller count and cane diameter with cane yield. Path analysis revealed the highest positive direct effect of millable cane number (0.812) on cane yield followed by single cane weight (0.682) and pol percent (0.550). However, stalk diameter and brix percent had considerable negative direct effects and indirect positive effects through single cane weight on cane yield. Therefore, in view of their significant positive association with cane yield, indirect effects of stalk diameter and brix percent via single cane weight should be considered during selection. Genotypes should be selected on the basis of millable cane number, single cane weight and pol percent for getting higher cane and sugar yield.

Optimizing Row Spacing to Ameliorate the Productivity of Spring Sugarcane (<i>Saccharum officinarum</i> L.)

One of the main reasons behind reduced cane yield is pathetic method of planting. Planting method and row spacing are the most important yield contributing factors in sugarcane. A field experiment was carried out in order to determine quality and yield of sugarcane in various spatial arrangements. Treatments are 180 cm spaced trenches with triple row strips; 180 cm spaced trenches with alternate row strips; 120 cm spaced trenches with double row strips and 60 cm spaced furrow with single row. Perusal of data revealed that 3.6%, 13.4%, 15%, 15.3% more cane diameter (cm), cane length (cm), stripped cane yield (t·haˉ1), sugar yield (t·haˉ1) were obtained from 180 cm spaced trenches with triple row strips as compared to conventional planting method i.e. 60 cm spaced furrows. While the number of millable canes mˉ2, polarity %, cane juice purity %, cane juice %, commercial cane sugar % and cane sugar recovery % remained non-significant by different planting techniques.

UNDERSTANDING POSTHARVEST QUALITY OF KIWIFRUIT IN RELATION TO SHOOT AND CANE VIGOR

Global kiwifruit production has expanded considerably. Over-softening and a low soluble solids concentration of kiwifruit after storage are the main factors associated with market satisfaction. Variability between kiwifruit batches, which is associated with season, orchard, pre- and postharvest practices, can result in fruit with unpredictable postharvest quality. The origin of fruit from different locations on a vine was used to explain the variation at harvest and postharvest quality. Fruit selected from different associations between shoot and cane vigor (evaluated by diameter) from vines of three orchards with demonstrated that fruit growing on terminated shoots was dominant. In addition, dry matter concentration and ripe soluble solids concentration were not affected by cane or shoot diameter. Further, fruit size was positively related to terminated shoot length and firmer fruit developed on non-terminated shoots compared with terminated shoots when assessed after ripening. These data were validated during the following year using data collected from eight orchards. Here, a comparison of fruit from non-terminated shoots with a small diameter (8.1-9.6 mm) growing on medium-diameter canes (22.4-24.5 mm) and from terminated shoots with a medium diameter (10.7-11.7 mm) growing on small-diameter canes (15.2-15.9 mm) demonstrated that terminated shoots produced softer fruit, and the nitrogen concentration in the pulp of these kiwifruits at harvest was negatively correlated with fruit firmness measured after 75 days at 0°C + 4 days at 20°C.

Marker-trait association study for sucrose and yield contributing traits in sugarcane (Saccharum spp. hybrid)

Linkage disequilibrium (LD)-based marker-trait association (MTA) was used to identify markers for sucrose and yield contributing traits in a panel of 108 sugarcane genotypes from sub-tropical India. Population structure (Q), kinship (K), and MTA study exploited a set of 989 marker loci generated from 123 genomic- and expressed sequence tag-SSR primers. The mixed linear model (MLM) coupled with a modified algorithm for population structure (Q) analysis was able to control both type I and type II errors and provided a deeper understanding of the genetics, population stratification and its manifestations on LD in the sugarcane genome. Significant associations were identified for four markers with cane diameter, seven markers each with cane length and number of millable canes (NMCs), eleven markers with number of nodes, six with sucrose per cent, and five markers with average cane weight. A total of 15 markers stable for all the 3 years of study explained 57 % trait variation for NMCs, 34 % for cane width, 27 % for cane length, 20 % for sucrose content, and 19 % for number of nodes. The frequent deviation of structure-based profiles from pedigree-based grouping in this complex heterozygous system reinforced the importance of using genotypic data for selection and breeding. The results contribute to a deeper insight of the complex genome and the identified MTAs could be exploited to fine-tune marker-assisted breeding programmes in genetically complex sugarcane crop.

Growth and development of ‘Illini Hardy’ blackberry (Rubus subgenus Eubatus Focke) under shaded systems

Blackberries (Rubus subgenus Eubatus Focke) of the Eastern United States commonly grow along forest edges and in disturbed sites, though the potential for introducing improved cultivars into managed forest systems has been little explored in agroforestry literature. Bare root ‘Illini Hardy’ blackberry plants were grown under three neutral shade cloth levels (20, 50, and 70 % irradiance relative to full sunlight) and a full sun control in an orchard system over one growing season. The plants were then excavated from the shade plots and the floricanes forced to fruit in a heated greenhouse after receiving a chilling treatment consistent with data published about the cultivar. Potential yield reflected by primocane yield components was only marginally affected by the light treatments, with no significant differences in primocane counts, cane length, or the numbers of nodes. Cane diameter and attributes of primocane architecture were significant, affecting crown geometries and resulting in the highest percent light interception among plants grown at 70 % relative irradiance. Maximum net photosynthesis rates increased at higher irradiance levels with little increase above 70 % full sunlight, although no differences were observed in whole plant biomass or biomass allocation. Flowering and harvest periods were more concentrated from plants receiving 70–100 % relative irradiance during flower initiation. These results suggest that vegetative phases of ‘Illini Hardy’ blackberry may benefit from partial shading with an optimum light intensity approximating 70 % of full sunlight, but that floral bud differentiation is delayed or incomplete at lower irradiance levels produced by whole canopy or intracane shading.

Nutrient uptake, sugarcane yield and economics of high sugar early genotypes of sugarcane (Saccharum sp hybrid complex) under various planting seasons and fertility levels in Bihar

A field experiment was conducted for 3 consecutive years (2006-2010) in two seasons (autumn and spring) on sandy loam soil of Bihar, Pusa (Samastipur), to find out the impact of early maturing high sugar genotypes and level of N-P and K fertilization on performance of sugarcane (Saccharum sp hybrid complex). The performance indicated significant superiority of CoSe 95422 to CoP 9301 in terms of germination (35.5 and 34.4 %), tillers (152 700 and 141 400/ha), cane length (204 and 201 cm) and cane diameter (2.32 and 2.25 cm) in autumn and spring season, respectively. CoSe 95422 exhibited significantly higher dry matter accumulation and leaf area index at all the growth stages during both the cropping seasons. Net assimilation rate increased substantially at the initial crop growth stages and declined thereafter. Genotype CoP 9301 achieved higher NAR (6.34 and 5.66 g/m2/day) during June- August, though it was failed to reach the level of significance during August-October. Number of millable canes exhibited marked variation among the genotypes in both the seasons. CoSe 95422 produced significantly highest cane yield during autumn (81.0 tonnes/ha) and spring season (73.2 tonnes/ha) respectively. The percentage increase in mean cane and sugar yield by autumn planted sugarcane over spring planted sugarcane was 9.7 and 11.27 %, respectively. However, maximum sugar yield was obtained by CoSe 95422. Further, it showed significantly higher N (206.8 and 176.5 kg/ha), P (18.5 and 16.9 kg/ha), K uptake (239.4 and 204.0 kg/ha), net return (` 55 430 and ` 46 500) and benefit: cost ratio (1.86 and 1.75) during autumn and spring season, respectively. Fertility level had significant impact on drymatter accumulation and leaf area index across the season as well as stages of growth. Significantly higher tillers (140 300 and 131 000/ha), cane length (208 and 204 cm), cane diameter (2.34 and 2.26 cm), millable cane (102 100 and 100 300/ha) and cane yield (85.2 and 77.6 tonnes/ha) were obtained with the application of 187.5 N + 46.4 P + 62.3 K kg/ha in autumn and spring season, respectively. Though all of these parameters except cane diameter in spring season were statistically similar to 150 N + 37.1 P + 49.8 K kg/ha. A significant increase in cane and sugar yield was observed up to 150 N + 37.1 P + 49.8 K kg/ha. The magnitude of increase in cane yield at 187.5 N + 46.4 P + 62.3 K, 150 N + 37.1 P + 49.8 K kg/ha over 112.5 N + 27.8 P + 37.4 K kg/ha were 37.6 and 30.9%, respectively, during autumn season. Whereas, these increased 35.7 and 28.0% respectively during spring season. Though, significant variation in sugar yield up to 150 N + 37.1 P + 49.8 K kg/ha was noticed during both the season. There was a significant increase in net return by increasing level of N+P+K/ha during both the season. Though, marked variation in benefit: cost ratio (1.87 and 1.75) was observed only up to 150 N + 37.1 P + 49.8 K kg/ha during autumn and spring season, respectively.

Economic Assessment of Sugarcane (Saccharum officinarum L.) through Intercropping

Sugarcane has pronounced importance to provide sugar for more than half of the global population. World population is enhancing day-by-day and production land is in the worst situation. The cultivated land is diminishing rapidly due to urbanization, road construction, and land deterioration. This crisis demands alternate research to raise crop productivity and maximize the economic returns per unit land for feeding the gigantic population. Sugarcane is a long duration crop and gave late net economic return. Intercropping in sugarcane received much attention and need to properly manage for getting higher net return from same unit area. It is becoming popular among farming community due to resourcefully utilization of land. Intercropping has the potential to inspire the farmers to get maximum economic return per acre per annum. For intercropping, wheat, gram, soybean, and potato were used as an intercrop in September-sown sugarcane. Triple row strip planting geometry of sugarcane with four intercropped (SC + Wheat, SC + Gram, SC + Soybean, and SC + Potato) and check with sole SC was used. Sugarcane was planted during September 2011- 12 and 2012-13 at research area University College of Agriculture, University of Sargodha, Pakistan. Randomized complete block design with three replications were used. Results showed that number of millable cane, cane diameter; unstripped and stripped cane yield and crop growth rate was significantly higher in sole sugarcane when compared with different intercrop in 2011-12 while trend was same in 2012-13. Cane diameter and un-stripped cane yield were statistically at par of intercrops SC + Soybean and SC + Potato while stripped cane yield of Sole SC and SC + Potato was statistically at par in 2012-13. In both the year of study, intercrops gave higher land equivalent ratio and net return over sole sugarcane planted while sole sugarcane gave maximum benefit cost ratio compared with other intercrops.

Influence of Salinity Stress on Growth Parameters and Yield of Sugarcane

A pot culture experiment was conducted to study the influence of salt stress on growth and yield component of four sugarcane varieties viz., C 92038, Co 85004, Si 94050 and Co 85036. The result of the study reveals that the growth parameter viz., LAI, LAD and CGR, RGR and SGR indicated that the derivation of LAI, CGR and SGR are the reliable growth parameters for assessing the genotypes for salt tolerance, as resistant genotypes Co 85004 and C 92038 performed better because of higher CGR, and SGR in present study. The important yield parameters viz., number of stalk per -1 , stalk length, number of inter nodes, inter nodal length, cane diameter and single cane weight were found to be affected under salt stress condition, which leads in overall yield reduction of 38.56 per cent in T2. However the extent of reduction was less in GA3 treated plants (18.50 %). Under salinity condition, the reduction in yield was less in C 92038 and Co 85004 (29.81 and 28.00 %) and it was found to be maximum in Co 85036 and Si 94050 (47.82 and 47.36 %). Irrespective of the genotypes, supplementing GA3 (150 ppm) as sett treatment and foliar application play role on imparting salt tolerance in terms of getting better growth and cane yield. Keywords: Sugarcane salinity, CGR, RGR, SGR, GA3, resistant and susceptible.

Berry Weight, Quality and Cane Biochemistry Changes in Relation to Cane Thickness of Own-Rooted and Grafted 'Tas-A-Ganesh' Grape

A field trial was conducted to determine the effect of cane thickness on berry quality and other biochemical parameters in 'Tas-A-Ganesh' grape at National Research Centre for Grapes, Pune, during the year 2008- 2009. Average bunch weight increased with increase in cane diameter. Own-rooted vines of cane thickness <6mm sprouted earlier than thicker canes. TSS of berries decreased with increase in berry size. Berries on grafted vines recorded lower TSS than on own-rooted vines. Biochemical parameters such as content of reducing sugars, carbohydrat and phenols were higher in grafted vines of cane thickness >10mm. Results indicate that thicker canes either on their own roots or on grafted vines are superior for yield and yield components, as also for physical properties of bunches and berries and total carbohydrate content of the canes.

Influence of Micronutrients on Yield and Quality of Sugarcane

The field experiment was conducted for 2 years to find out the effect of application of micronutrients on yield and quality of sugarcane in sandy loam soils during 2009 and 2010. The study indicated that all the yield traits viz., NMC, cane length, cane diameter and cane yield were significantly influenced by the application of zinc and Iron. Non significant response was observed with Boron application for growth parameters except for cane diameter. Data on juice quality parameters i.e. sucrose % at harvest showed significant influence due to soil application of boron @ 10 kg/ha followed by FeSO4 spray @ 2 % twice at 30 and 60 days after planting. Sugar yield increased significantly with application of all micronutrients. Regression model was developed which indicated the dependency of sugar yield on cane yield.

Production Potential and Soil Fertility Status of Ratoon Sugarcane (Saccharum officinarum L.) as Influenced by Time and Level of Earthing Up and Nitrogen Levels in North-Eastern Uttar Pradesh, India

<p>A field experiment was carried out during the spring seasons of 2008-09 and 2009-10 at Varanasi, Uttar Pradesh to find out exact time of earthing up with level of earthing up and optimum doses of nitrogen for getting higher productivity, monetary returns, and changes in the fertility status of soils after harvest of ratoon sugarcane (<em>Saccharum officinarum</em> L.). Twentieth fifth April earthed crop produced significantly more height of tillers, leaf area index at maximum tillering stage, grand growth stage and at harvest, dry matter/tiller at maximum tillering stage at grand growth stage and at harvest, cane length, cane diameter of top, middle and bottom, weight of cane, cane yield, monetary returns, B/C ratio, N, P and K uptake except number of tillers/ha, number of millable cane/ha and net available soil nutrient after the harvest of ratoon crops as compared to 25<sup>th</sup> May and 25<sup>th</sup> June respectively. Twentieth cm height of earthing up from the ridge also significantly increased all the above parameters such as height of tillers, LAI of maximum tillering stage, grand growth stage and harvest, dry matter/tiller at maximum tillering stage, grand growth stage and at harvest, cane length, weight of cane and cane yield than that of 10 cm earthed crop in both the ratoon crops. Application of 210 kg N/ha linearly and significantly increased number of tillers/ha at 60 and 120 days after ratooning, height of tillers at 120 days after ratooning, LAI at maximum tillering stage, grand growth stage, and at harvest, dry matter/tiller at maximum tillering stage, grand growth stage and at harvest, number of millable cane, cane length, cane weight, cane yield, monetary returns, B/C ratio and N, P, K uptake followed by 180 kg N/ha. Ratoon crop showed that there was a build up of nitrogen and phosphorous but depletion in potassium content of the soil. 210 kg N/ha with earlier earthed at 25<sup>th</sup> April to a level of 20 cm was found optimum for obtaining higher yields and monetary returns.</p>

Evaluation of Drought Tolerance Potential of Elite Genotypes and Progenies of Sugarcane (Saccharum sp. hybrids)

In order to identify drought tolerant genotypes and study the pattern of segregation for drought, 28 elite sugarcane hybrids and 165 progenies from a proven commercial cross (Co 740 × Co 775) were evaluated for sugar yield attributes and biochemical parameters under normal and drought conditions. In the genotypes, higher reduction in drought in relation to the normal condition were observed for internode length (45.76 %), single cane weight (25.5 %), NMC (22.8 %), cane length (20.10 %) and sucrose content (18.73 %), while cane diameter (2.92 %), internode number (3.58 %) and Brix (−6.99 %) showed marginal variation. Similar reduction in cane height (35.05 %) and internode length (25.13 %) in the progenies indicated that cane length was more adversely affected by drought and the reduction was through shortening of internodes than reduction in internode number. These two easily scorable parameters in field and showing significant positive correlation under normal and drought conditions could serve as reliable characters in drought screening. Nitrate reductase activity showed reduction in the genotypes (39.11 %) and progenies (44.95 %), while proline accumulation and activities of superoxide dismutase and peroxidase almost doubled in the genotypes and progenies. The tolerant genotypes viz. Co 740, ISH 100, NS 83/247, Co 85019, Co 997 and Co 99008 could be utilized in crop improvement, while Co 419, Co 8021, Co 775 and Co 8368 were susceptible. Higher proportion of drought tolerant genotypes reflected the genetic nature of sugarcane hybrids with genome contribution from the drought tolerant species S. spontaneum.. The population of 165 progenies was categorized into five classes of varying levels of tolerance that followed a normal distribution and hence its value as an immortal mapping population for genetical and molecular studies on drought tolerance.

Genetic Parameters and Breeding for Yield in Red Raspberry

For most small fruit-breeding programs, high yield is a key objective and breeders face a number of challenges breeding for high yield, including interaction of environmental influences and the high cost of yield measurements. Red raspberry (Rubus idaeus) yield is determined by a number of yield components (YC), including cane number, cane length, number of fruiting laterals, fruit numbers, and fruit size. The ultimate goal for breeders would be to be able to select for high-yield genotypes using key YC as early in the life of the plant as possible. In this study we set out to determine how individual components of yield are inherited, determine which components contribute the most to total yield, and investigate whether it is possible using key components to make selections for high-yielding genotypes on 1- and 2-year-old plants. We estimated variance components, heritabilities, phenotypic and genotypic correlations, and breeding values for yield and YC from 1008 genotypes based on 85 families derived from 45 parents harvested over three seasons in Washington state. Narrow-sense heritability estimates varied from moderately low [0.2 for number of canes (NCAN)] to moderately high [0.69 for berry weight (BWT)]. In general, all YCs were positively correlated with total yield (TYLD). The highest genetic correlation with TYLD was found for BWT (0.8), followed by cane length (CLEN) (0.54) and number of fruit per lateral (NFRT) (0.5). NCAN had the lowest genetic correlation with TYLD (–0.03). Genotype × year (G×Y) interaction was higher for some YCs than others. Berry weight, lateral length (LLEN), and NFRT were found to be the most stable overall seasons and the interaction was higher between the first and second years than between the second and third years of the study. To determine the most important YC, we calculated the correlations between the product of all combinations of subsets of the YC breeding values and TYLD. Berry weight, CLEN, and cane diameter (CDIA) were found to be the most important for 2009, 2010, and 2011, respectively. The two most important YCs were LLEN and BWT and this was consistent overall seasons. We demonstrate that it is possible to select high-yielding genotypes by measuring key components such as LLEN, CLEN, and BWT in the first and second fruiting seasons.

Genetic Diversity and Selection Among Drought Tolerant Genotypes of Sugarcane Using Microsatellite Markers

The present study is an attempt to combine drought tolerance with yield and quality traits guided by molecular diversity estimates. Using thirty primers of sugarcane specific sequence tagged microsatellite markers, genetic diversity of 28 elite clones used in sugarcane improvement was estimated. Similarity indices among 378 possible cross combinations involving these parental clones estimated by Jaccard’s coefficient analysis showed that 85 combinations were more similar (SI ≥ 0.80), 45 combinations were diverse (SI ≤ 0.60) and the remaining 248 combinations exhibited intermediate diversity (SI values between 0.60 and 0.80), indicating the existence of moderate genetic divergence in the clones studied. Twenty-five out of 28 genotypes being drought tolerant, use of genetic diversity information in family selection for realizing higher yield and quality with drought tolerance was explored through progeny analysis of 14 crosses comprising of six genetically diverse, five with medium diversity and three less diverse crosses. Screening of 1,448 progenies from these crosses in first clonal trial under normal and drought conditions for juice quality quantified as Hand refractometer Brix, cane diameter and single cane weight at maturity and per cent reduction for these parameters due to drought led to 766 selections. Higher percentages of selection from genetically less similar crosses (SI below 0.80) and a significant negative correlation (−0.7976) between selection per cent of each cross and similarity index highlighted the usefulness of selecting more diverse combinations for the genetic improvement of sugarcane for combining drought tolerance with yield and quality characters in sugarcane.

From sugar industry to cane industry: investigations on multivariate data analysis techniques in the identification of different high biomass sugarcane varieties

Apart from sugar production, the sugarcane plant is now viewed as a high value lowcost feedstock for renewable energy. However, in depth studies on the biomass potential of the crop are relatively new and current varieties have not been optimised to achieve the required high biomass yield for different end-uses. The objective of this study was to examine the possibility of using multivariate data analysis (MVDA) techniques in the selection of different types of high biomass canes. Sixty genotypes of different generations of crosses were evaluated for 18 inter-related traits. Principal component analysis compressed the different characters into five major principal components (PCs). The first two explained 77 % of total variation. PC1 emphasised on the cane quality traits while PC2 stressed on biomass characteristics. The biplot with the two PCs was very helpful in visualising the existing variations in the population. Cluster analysis defined six major groups in the population. Candidates from three of them were found suitable for commercial exploitation, for either sugar, fibre, or both as the main end-products. The MVDA techniques were thus found to be very effective in assessing the extent of genetic divergence between genotypes in the population and in the selection of different types of high biomass canes for multipurpose use. It was also clear that sucrose content was positively associated with cane diameter while high fibre varieties tended to be thinner and taller than the traditional commercial varieties.

Effects of Gluconacetobacter diazotrophicus on seed cane produced through micro-propagated plantlets in sugarcane (Saccharum spp hybrid complex) under sub-tropics

Field experiment was conducted to evaluate the performance of micropropagated plantlets inoculated in vitro with Gluconacetobacter diazotrophicus on the population counts of diazotroph, plant growth, yield, quality and ultimately planting material of sugarcane cultivar CoS 96268. Maximum cell counts (5.8 × 105 cells/g fresh weight) was obtained in the in vitro, treated micropropagated plantlets-followed by untreated micropropagated plantlets (4.7 × 104 cells/g fresh weight) while it was only 3.7 x104 cells/g fresh weight in conventionally grown plants. The highest cell counts of Gluconacetobacter diazotrophicus was recorded at grand growth stage which decreased at maturity. Inoculation with diazotroph improved dry matter accumulation specially in roots accompanied by higher uptake of nitrogen and potassium in micropropagated plantlets. There was significant increase in number of millable canes, cane length, number of nodes, cane diameter and cane yield. Besides, treated plantlets produced 5.45 and 1.52 times higher planting material (3 budded setts) over conventionally grown plants and un-treated micropropagated plantlets, respectively. Results signify the use of inoculation with diazotrophic bacteria in micropropagated plantlets for faster multiplication of disease-free healthy seed cane of sugarcane varieties for their adoption.