Horticultural Classification of Citrus Cultivars

Globally, citrus fruits are grown over an area of 11.42 million ha with 179.0 million tons production. China with 82.7 m tons production is the major producer of citrus fruits followed by Brazil (18.14 m tons) and India (10.53 m tons) (FAOSTAT, 2019). All commercially used scion and rootstock cultivars belong to the genus Citrus, except kumquats, Fortunella spp., and Poncirus trifoliata, which are used as rootstock only all over the world. Worldwide citrus cultivars divided into four, reasonably-well-defined horticultural groups: the Sweet oranges, the mandarins, the grapefruits and the pummelos and the common acid members. The true or ‘biological’ citrus, including species of Citrus (C. reticulata, C. maxima and C. medica), share certain characteristics, however, these are clearly differentiated according to the morpho- taxonomic traits. Hundreds of different citrus cultivars are available. Many varieties were chance finds from natural populations, and not the product of intentional breeding efforts. Other varieties in common use have originated from planned citrus hybridization and breeding efforts from worldwide. Most of the readers will be well acquainted with the cultivated types of Citrus scion and rootstocks. This chapter provides ripening season information for worldwide, farmers/gardeners have had success with citrus in many different regions of world where tropical/subtropical climatic conditions occur

Optimizing Recovery of Hybrid Embryos from Interspecific Citrus Crosses of Polyembryonic Rough Lemon (Citrus jambhiri Lush.)

The prevalence of rough lemon rootstock in India is presently threatened by the spread of Phytophthora root rot. Developing an alternative Phytophthora-resistant rootstock that also withstands other abiotic constraints is a priority for a sustainable citrus industry in India. Complementary progenitors can be found in citrus germplasm to combine the desired traits, particularly between Citrus and Poncirus, a closely related genus. The production of hybrids accumulating the desired dominant traits, irrespective of the heterozygosity level of the parents, is an effective way to develop new candidate rootstocks. Rough lemon was hybridized with Swingle citrumelo, X-639 citrandarin, and GouTou Cheng. A reliable method was developed for greater recovery of hybrid seedlings from these crosses on the basis of morphology and simple sequence repeat (SSR) markers. The greatest proportion of hybrid seedlings resulted from embryo rescue at 95 days after pollination (DAP) (48.5% in rough lemon × X-639 citrandarin and 56.7% in rough lemon × Swingle citrumelo) on the basis of multifoliate leaves. The proportion of hybrid seedlings decreased with increase in embryo development stage after 95 DAP until the last stage of observation (125 DAP). Significantly higher proportion of multifoliate seedlings was recovered by in vitro culture compared with in vivo germination from the mature seeds (26.9% vs. 5.2%, respectively). Swingle and X-639 citrandarin are not homozygous for the multifoliate allele from Poncirus, and GouTou Cheng lacks the multifoliate allele; thus, unifoliate hybrids were selected from all crosses on the basis of SSR marker genotypes

Effect of Low-Density Polyethylene on Shelf Life and Fruit Quality of Indian Gooseberry (Emblica officinalis Gaertn.)

Indian gooseberry (Emblica officinalis Gaertn.) is an indigenous important hardy underutilized fruit crop of India. The objective of the present investigation was to evaluate the effect of Modified Atmospheric Packaging- Low Density Polyethylene (MAP-LDPE) on storage life and fruit quality (physico-chemical attributes) of different cultivars of Aonla fruits up to 12 days. Physico-chemical attributes such as Physiological Loss in Weight (PLW), Decay loss, Total Soluble solids Acidity, Ascorbic acid and Sugars were determined for Aonla cultivars viz. NA-6, NA-7, NA-10, NA-25, NA-26, NA-27 and Francis in this experiment. The pooled results revealed that MAP-LDPE was able to reduce the Physiological Loss in Weight and Decay loss of Aonla fruits up to twelfth day of storage. Higher retention of Ascorbic acid and Acidity content was observed during 12 days of storage. Total Soluble solids and Sugars content was low in LDPE-MAP as compared to control storage condition in different cultivars of Aonla. The findings of the study will be useful in increasing the availability of Aonla fruits and enable for its long-distance transportation and subsequent marketing

Inflammatory impact on tissues surrounding the dental implant of singular abutments bonded onto titanium base – A randomized controlled trial

Introduction: In dental implants, the biochemical connection between titanium (ti) and bony tissue has been well established. The properties of dental implants such as osseointegration and stability depend upon composition, design of the implant, connection, and design of the abutment, and additional removal of abutments. Recently, laser-generated micro-grooved surface (LSS) and TI abutments are the main focus of preventing peri-implant inflammation. Objectives: To assess the inflammatory impact of singular abutments bonded onto titanium bases on tissues surrounding the dental implant. Methods: Twenty subjects were enrolled. Only those subjects were enrolled who were scheduled to undergo prosthetic rehabilitation of missing teeth. Random division of subjects was done. Group A: Test abutment group and Group B: Control abutment group. The test abutments comprised Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) titanium abutments bonded onto titanium abutments. However, control abutments were customized and only one-piece CAD/CAM titanium abutments were enrolled.On 6 months and 12 months of follow-up, the clinical and radiographic examination was done. Assessment of the bone level changes, clinical variables, and IL-1b levels was assessed. Results: Mean IL-1b levels in Group A subjects at baseline, 6 months, and 12 months were 1.52 pg/mL, 1.69 pg/mL, and 1.55 pg/mL, respectively. Mean IL-1b levels among the patients of group B at baseline, 6 months, and 12 months were 1.56 pg/mL, 1.71 pg/mL, and 1.54 pg/mL, respectively. Conclusion: Within the limitation of the study, it can be concluded that the impact on the inflammatory condition of surrounding tissues of dental implant does not vary significantly between single abutments bonded onto Titanium bases and singular abutments

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Not AvailableIn this changing climate scenario, rapid increase of human population resulted in increased demand of food production. During the last century crop plants have been improved through classical breeding techniques and numerous varieties of several crops have been developed across the world. However conventional breeding in improving crop plants is constrained due to genetic erosion, genetic drag, reproductive obstacles and usually take longer time. Thus, there is an urgent need for the novel breeding and biotechnology-assisted crop improvement, which ultimately aimed to obtain novel plant traits. Many novel techniques such as marker assisted selection, marker assisted back cross breeding, marker assisted gene pyramiding plays crucial role in improvement of crop plants. Advancement in plant genetic engineering (genetic transformation and genome editing) have made it possible to transfer gene into crop plants from unrelated plants and even from non-plant organism. These biotechnological approaches are a great option to improve crop plants with significant commercial properties such as increased biotic stress resistant or abiotic stress tolerances; nutrition; yield and quality.Not Availabl

Comprehensive genome-wide identification and transferability of chromosome-specific highly variable microsatellite markers from citrus species

Abstract Citrus species among the most important and widely consumed fruit in the world due to Vitamin C, essential oil glands, and flavonoids. Highly variable simple sequence repeats (SSR) markers are one of the most informative and versatile molecular markers used in perennial tree genetic research. SSR survey of Citrus sinensis and Citrus maxima were identified perfect SSRs spanning nine chromosomes. Furthermore, we categorized all SSR motifs into three major classes based on their tract lengths. We designed and validated a class I SSRs in the C. sinensis and C. maxima genome through electronic polymerase chain reaction (ePCR) and found 83.89% in C. sinensis and 78.52% in C. maxima SSRs producing a single amplicon. Then, we selected extremely variable SSRs (> 40 nt) from the ePCR-verified class I SSRs and in silico validated across seven draft genomes of citrus, which provided us a subset of 84.74% in C. sinensis and 77.53% in C. maxima highly polymorphic SSRs. Out of these, 129 primers were validated on 24 citrus genotypes through wet-lab experiment. We found 127 (98.45%) polymorphic HvSSRs on 24 genotypes. The utility of the developed HvSSRs was demonstrated by analysing genetic diversity of 181 citrus genotypes using 17 HvSSRs spanning nine citrus chromosomes and were divided into 11 main groups through 17 HvSSRs. These chromosome-specific SSRs will serve as a powerful genomic tool used for future QTL mapping, molecular breeding, investigation of population genetic diversity, comparative mapping, and evolutionary studies among citrus and other relative genera/species

Marker-assisted pyramiding of lycopene-ε-cyclase, β-carotene hydroxylase1 and opaque2 genes for development of biofortified maize hybrids

Abstract Malnutrition affects growth and development in humans and causes socio-economic losses. Normal maize is deficient in essential amino acids, lysine and tryptophan; and vitamin-A. Crop biofortification is a sustainable and economical approach to alleviate micronutrient malnutrition. We combined favorable alleles of crtRB1 and lcyE genes into opaque2 (o2)-based four inbreds viz. QLM11, QLM12, QLM13, and QLM14 using marker-assisted backcross breeding. These are parents of quality protein maize versions of two elite hybrids viz. Buland and PMH1, grown in India. Gene-based SSRs for o2 and InDel markers for crtRB1 and lcyE were successfully employed for foreground selection in BC1F1, BC2F1, and BC2F2 generations. The recurrent parent genome recovery ranged from 88.9 to 96.0% among introgressed progenies. Kernels of pyramided lines possessed a high concentration of proA (7.14–9.63 ppm), compared to 1.05 to 1.41 ppm in the recurrent parents, while lysine and tryptophan ranged from 0.28–0.44% and 0.07–0.09%, respectively. The reconstituted hybrids (RBuland and RPMH1) showed significant enhancement of endosperm proA (6.97–9.82 ppm), tryptophan (0.07–0.09%), and lysine (0.29–0.43%), while grain yield was at par with their original versions. The dissemination of reconstituted hybrids holds significant promise to alleviate vitamin-A deficiency and protein-energy malnutrition in developing countries