S. K. Sandhu

Field performance of micropropagated plants and potential of seed cane for stalk yield and quality in sugarcane

Two field experiments were conducted to ascertain the potential of micropropagation technique for faster production of seed cane by using tissue culture plants raised through apical meristem culture in first generation (TC 0) followed by clonal propagation through cane setts in next generation (TC1). About 18, 520 plants, produced from a single shoot through micropropagation, were required at row to row and plant to plant spacing of 90 and 60 cm, respectively as compared to 88 quintal of cane seed in conventional methods for planting in an area of one hectare. Multiplication ratio was 100–150 times using tissue culture plants as compared to 11–12 using conventional cane setts, leading to drastic reduction in seed cane requirement. The TC 1 exhibited superiority over vegetatively propagated conventional crop for millable canes and stalk yield by 17 and 10.4 per cent, respectively. Though the single cane weight and cane diameter (non-significantly) were slightly lesser in TC1 as compared to conventional crop, this did not distress its potential as seed crop. The incidence of Ratoon Stunting Disease (RSD) and Leaf Scald Disease (LSD) was very low in TC 1 crop as compared to conventional crop. The findings established the potential of tissue culture technique for the production of quality seed free of pests and pathogens in the existing varieties and rapid multiplication of newly released varieties for quick adoption by the growers.

Sucrose Accumulation and Internodal Soluble Invertase Isoenzymes in Plant and Ratoon Crops of Sugarcane

Accumulation pattern of sucrose and hexoses in relation to activities of invertases in stem tissue of plant and ratoon crops of CoJ88 (mid maturing variety) has been investigated at different physiological stages of cane growth. At each stage of crop development, sucrose content was relatively more in ratoon crop than plant crop, whereas the reducing sugar content was relatively less in ratoon crop than plant crop. The activity of soluble acid invertase in stem was found to be highest at stem elongation stage and declined thereafter in both plant and ratoon crops. The activity of soluble acid invertase (pH 5.5) was markedly lower in ratoon crop as compared to plant crop at each stage of crop development. Higher level of sucrose and lower level of acid invertase in ratoon crop indicates higher sink strength and better juice quality of ratoon crop. The activity of neutral invertase (pH 7.0) increased with the advancement of the cane growth in both the crops. Three isoenzymes of soluble acid invertase in plant crop namely A-I, A-II and A-III and two isoforms of this enzyme in ratoon crop namely A-I and A-II were identified at stem elongation stage. Neutral invertase isoenzyme was not detected in both the crops at this stage. At maturation stage, one acid invertase isoform i.e. A-I was obtained in both the crops along with four neutral invertase isoenzymes in plant crop i.e. N-I, N-II, N-III and N-IV and two isoforms of this enzyme in ratoon crop i.e. N-I and N-II. These invertase isoforms differed with respect to their Km and Vmax values. From the temperature effect on Km and Vmax values, the energy of activation (Ea) and enthalpy change (∆H) of invertase isoenzymes were calculated at stem elongation and maturity stages and compared among isoenzymes of plant and ratoon crops in relation to sucrose accumulation.

GGE Biplot Analysis for Cane and Sugar Yield from Advanced-Stage Sugarcane Trials in Subtropical India

The performance of quantitative traits in sugarcane (Saccharum spp. complex) often varies across diverse environments because of significant genotype-by-environment interaction (GEI). Our objective was to assess performance stability of 20 advanced sugarcane genotypes across six environments, including two crop seasons in Punjab. Data were obtained on cane yield (t/ha), sucrose % juice, and commercial cane sugar % at harvest and subjected to GGE [genotype (G) plus genotype-environment (GE)] biplot analysis, which revealed high positive correlations between spring and autumn crop seasons at all locations for all measured traits. This implied that genotypes could be evaluated in either crop season, which should reduce testing cost and time. Test environment Faridkot (FDK) spring, being both discriminating and representative, was an ideal test environment for selecting generally adapted genotypes for cane yield. Similarly, Ludhiana (LDH) autumn was an ideal test environment for selecting generally adapted genotypes for quality traits. Co 0238 and CoPb 08214, having high mean performance and stability across environments for cane yield and quality traits, were identified as ideal genotypes. These genotypes can be exploited commercially for the entire state of Punjab. The GGE biplot helped identify a specifically adapted genotype, CoH 119, which was the best performer in Gurdaspur (GDSP) in both crop seasons.

Genomic-Assisted Breeding in Oilseed Brassicas

The oilseed brassicas, world’s third most important source of vegetable oil with recently gained interest as a source of biodiesel, occupy a prominent place in the world’s agrarian economy and are grown in more than 50 countries across the globe. Improvement in nutritional profiling of Brassica oil and its defatted oil cake has vastly spread the production domain of rapeseed-mustard in the world. Consistent breeding efforts led to conversion of almost all Brassica napus into present-day canola-quality cultivars, and intensification of this quality trait in Brassica juncea too is leading its expansion in drier and low rainfall areas of the world. The good agronomic performance and the energetic balance of Brassica carinata in semiarid temperate climate and under low cropping system have generated a new interest in this species as an oilseed crop. Though, a young species with a short domestication history, Brassica napus has gained a huge attention of researchers and consequently, has witnessed a steady progress during last four decades. The conventional breeding as well as modern biotechnological tools has led to the improvement of various agronomically important quantitative and qualitative characters in oilseed brassicas.

Advances in Breeding for Resistance to Insects

Traditionally, researcher has put more focus on disease resistance than on insect resistance, but the adverse effects of excessive use of pesticides on human health, environment, phyto-sanitation, market access, and global trade have led to renewed interest in breeding for resistance to insects. The development of insect-resistant crops is a sustainable way to manage pests. In this chapter, historical impact of resistance to insects in ensuring food security has been cited. The identification of new sources of resistance to insects and better understanding of resistance mechanisms have opened new avenues in the field of host-plant resistance (HPR). New insights into structural and functional aspects of genes conferring resistance to insects (R-genes) during the past two-three decades and their proper utilization, by researchers, have been discussed. The breeding methods for developing resistance to insects in self- and cross-pollinated crops have been elaborated. The findings on complex host-pest interactions and overlapping of controlling genes or quantitative trait loci (QTL) for resistance to biotic and abiotic stresses emphasizes the adoption of holistic approaches to develop insect-resistant crops.

Insect-Plant Interrelationships

The green plants and insects represent the two dominant groups of living organisms on Earth. The green plants occupy the most capacious segment among all biological organisms, whereas the insects are the most specious group. These two ‘empires’ are interconnected as well as interdependent. Green plants are the primary producers of food, and all animals being heterotrophs depend directly or indirectly on plant-produced food. In turn, nearly three fourths of all angiosperms require the services of insect pollinators. The entomophilic flowering plants and their insect pollinators thus represent the most evident and widely applicable example of mutualism among living organisms. But a wide variety of phytophagous insects also flourishes, diversifies and sustains on these plants. Consequently, the plants have evolved a dizzying array of morphological and biochemical (constitutive as well as induced) barriers for protection against insects and other herbivores. Evolutionary interactions between plants and insects may have contributed to the increased biodiversity and success of both these groups. The study of these interrelationships, as outlined in this chapter, is of great practical significance for the future agricultural production. The development of pest-resistant cultivars of crop plants and progress in integrated pest management both require an intricate understanding of insect-plant relationships. State-of-the-art techniques such as mutant analysis, metabolomics, RNAi and proteomics developed during the last three decades have been instrumental in providing improved insight into these interrelationships.

Breeding Insect Resistant Crops for Sustainable Agriculture

The green plants and insects represent the two dominant groups of living organisms on Earth. The green plants occupy the most capacious segment among all biological organisms, whereas the insects are the most specious group. These two ‘empires’ are interconnected as well as interdependent. Green plants are the primary producers of food, and all animals being heterotrophs depend directly or indirectly on plant-produced food. In turn, nearly three fourths of all angiosperms require the services of insect pollinators. The entomophilic flowering plants and their insect pollinators thus represent the most evident and widely applicable example of mutualism among living organisms. But a wide variety of phytophagous insects also flourishes, diversifies and sustains on these plants. Consequently, the plants have evolved a dizzying array of morphological and biochemical (constitutive as well as induced) barriers for protection against insects and other herbivores. Evolutionary interactions between plants and insects may have contributed to the increased biodiversity and success of both these groups. The study of these interrelationships, as outlined in this chapter, is of great practical significance for the future agricultural production. The development of pest-resistant cultivars of crop plants and progress in integrated pest management both require an intricate understanding of insect-plant relationships.