Maintenance Breeding Research Articles

Maintenance Breeding in Pigeonpea [Cajanus cajan (L.) Millspaugh] — An Assessment and Advanced Strategies

AbstractThe sustainable maintenance breeding of pigeonpea germplasm, genetic stocks, released cultivars, and hybrid parents is a tough job. The prime reason for their genetic contamination is the insect‐aided cross‐pollination. Although various public and private seed agencies are involved in maintenance breeding to produce different grades of pigeonpea seeds, but the limitation of resources and low priority make it difficult to meet the national seed requirements. This manuscript, aside from reviewing the present pigeonpea maintenance breeding methods, their limitations, and accomplishments, also highlights some advanced breeding and genomics approaches to enhance the efficiency of maintenance breeding.

Breeding of Okra for Resistance to Yellow Vein Mosaic Virus

Okra (Abelmoschus esculentus L. Moench) commonly known as Lady’s finger or Bhendi is most delicious vegetable relished worldwide. The productivity of okra has been low in recent times due to various reasons viz., inadequate use of fertilizers, irrigation and occurrence of various pest and diseases. In India okra crop is highly susceptible to yellow vein mosaic virus (YVMV) disease probably due to warm tropical climate and intensive crop cultivation which supports the survival of whitefly population round the year. Host plant resistance to virus is one of the most practical, economical and eco-friendly strategies for reducing yield loss in okra. Identification of stable and reliable sources of resistance to viral diseases is an important step in future breeding programme. Understanding the genetics of resistance in donor parent helps in choosing suitable breeding method and attempts should be made to incorporate broad spectrum resistance through gene pyramiding and develop okra varieties with desirable resistance or tolerance to okra YVMV followed by maintenance breeding.

Niger improvement : Current status and future strategies

The present research efforts of breeding are reviewed in relation to the potential, considering the niger cultivation by resource poor farmers. The history of domestication and the diversity in the plant genetic resources is critically analysed for the formulation of crop improvement strategies with the emphasis on enhancing the average low yield levels in India and in the African subcontinent. The utilization of primary gene pool and the potential uses of wild species are included. Niger improvement is analysed considering population improvement, development of superior inbreds and future strategies for hybrid development. Further biotechnology, mutation and resistance breeding for biotic and abiotic stresses are considered for the production of agronomic types with wider adaptation. Niger being a cross pollinated crop, where seed quality is a serious concern, maintenance breeding and nucleus seed production is covered in detail, since 30-50 per cent productivity improvement can be realised, easily through the intervention of quality seed supply. The production and protection technologies are reviewed for improvement inniger productivity. The potential areas for future line of research are indicated for productivity improvement in niger.

Study of Morphological Qualitative and Quantitative Characterization of Different Traits in Tomato (Solanum lycopersicum L.) Genotypes

Tomato is classified as a warm-season crop and is characterized by two distinct plant growth habits: determinate and indeterminate. The flowers of tomatoes are typically bisexual and possess both male and female reproductive structures, making them perfect flowers. The stigma of the flower is surrounded by a protective anther cone, which promotes self-pollination. This self-pollination trait in tomato plants facilitates their maintenance breeding, and simple selection methods can be employed to effectively improve the crop. The current investigation involved the characterization of twenty-five tomato germplasm genotypes. The experimental was carried out during rabi season 2021-2022 and 2022-2023 at Horticulture Research Centre, College of Horticulture, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut. Seedlings of tomato were transplanted at spacing of 60 x 45 cm in randomized block design with three replications. Data was collected based on eight qualitative traits, namely, plant growth habit, leaf colour, flower colour, fruit size, fruit shape, fruit colour, fruit surface, and stem end fruit shape. The tomato genotypes demonstrated significant variability in all qualitative traits, with the exception of the fruit surface trait. This highlights the importance of focusing on these traits in future crop improvement programs for tomato.

Recent trends in crop breeding, the varietal induction in seed chain and its impact on food grain production in India

Food grains in India achieved an all-time high production (310.74 mt) during 2020-21. Varietal and seed replacement rates played an important role in achieving this milestone. A total of 1646 varieties of food crops comprising 1273 of cereals and 373 of pulses were released from 2011 to 2022. Of these 977 varieties consisting of cereals (667) and pulses (310) have been inducted into the seed chain during 2020-21. New breeding technonologies such as bio-fortification of food crops and marker-assisted breeding were applied to improve crop varieties with respect to specific desirable traits. A total of 65 bio-fortified varieties comprising rice (8), wheat (28), maize (14), pearl millet (9), finger millet (3), little millet (1) and lentil (2) have been released with improved levels of proteins, essential amino acids (lysine, tryptophan), vitamins (pro-vitamin A) and micro/macro-nutrients (zinc, iron, calcium). Marker-assisted breeding adopting foreground and background selections with targeted gene(s) utilizing molecular markers such as RFLPs, SSRs, CAPs, STS and INDEL resulted in to the development and release of 66 cultivars comprising rice (43), wheat (5), maize (10), pearl millet (2) and chickpea (6) with one/and or combination of traits such as tolerance to biotic/abiotic stresses, herbicide tolerance, nutrient use efficiency, earliness, nutritional and other quality traits. These non-genetically modified crop varieties are expected to play vital role in achieving food and nutrition security in India. The paper also provides insight in to the maintenance breeding of food crops. The analysis of seed requirement and availability during 2010-11 to 2020-21 revealed that seed requirements for cereals and pulses have increased consistently by 31.6% and 62.3%, from 186.8 to 245.8 lakh q and 22.3 to 36.2 lakh q, respectively. The production of rice, wheat, maize, pearl millet and pulses during 2020-21 increased over that of 2010-11 by 27.4%, 26.0%, 45.2%, 4.4% and 41.3%, respectively. The productivity of sorghum was higher by 18.9% over that of 2010-11 but production decreased by 31.7% on account of a reduction in acreage by 42.5% during the corresponding period. The net per capita availability of food grains increased, by 17.2% from 159.5 kg to 187.0 kg during this period. The cereals and pulses production needs to be up-scaled by 5.3% and 24.4% to meet the demand by 2030 from 285.28 mt and 25.46 mt, respectively, in 2020-21, with almost the similar acreage, degrading and depleting natural resources, thus, requiring a greater focus on enhancing yield/ha. Crop-specific breeding programmes should be accelerated with the adoption of new technologies like GM, gene editing, marker-assisted selection and speed breeding to address the challenges of climate change and degrading natural sources.

Testing authenticity of certified paddy seed with user friendly Morpho-molecular tool- kit

In the present investigation, twenty nine rice cultivars were characterized using grain morphological characters and molecular markers to develop a morpho- molecular tool kit for application in authenticity testing of the certified seed lot and in maintenance breeding. The study suggested that identification of rice varieties is possible with grain morphology and molecular markers. Using grain morphological characters, seven varieties were uniquely identified viz., Prafulla, Numali, Dikhow, Dhanashree, Basundhara, Jalkuwari and Bhugali. Molecular fingerprints were generated based on SSR polymorphism. Using the present set of SSR markers, eight rice varieties viz., Gitesh, Jalashree, Ranjit, Jaymati, Bhugali, Ranjit sub-1, Numali, and Piyali, were distinguished with RM 12, RM 25, RM 190, RM 307 and RM 287on the basis of the unique banding pattern. In the phylogenetic relationship based on grain morphology, Dikhow was identified as an outlier, which is unique for the grain length, whereas based on SSR data, variety Praffulla was identified as an outlier with unique medium grain width. Key words: Rice, SSR marker, Diagnostic grain characters, Genetic purity &nbsp

Diversity and Relationships among Neglected Apricot (Prunus armeniaca L.) Landraces Using Morphological Traits and SSR Markers: Implications for Agro-Biodiversity Conservation.

Apricot (Prunus armeniaca L.) is an economically important tree species globally cultivated in temperate areas. Italy has an ample number of traditional varieties, but numerous landraces are abandoned and at risk of extinction because of increasing urbanization, agricultural intensification, and varietal renewal. In this work, we investigated the morphological and genetic diversity present in an ex-situ collection of 28 neglected varieties belonging to the so-called “Vesuvian apricot”. Our aim was to understand the level of diversity and the possible link between the promotion of specific fruit types (e.g., by public policies) and the intraspecific variation in apricot. The combination of five continuous and seven categorical traits allowed us to phenotypically distinguish the varieties; while fruit quality-related attributes displayed high variation, both apricot size and skin colour were more uniform. The twelve fluorescent-based Simple Sequence Repeats (SSRs) markers identified cultivar-specific molecular profiles and revealed a high molecular diversity, which poorly correlated with that described by the morphological analysis. Our results highlighted the complementary information provided by the two sets of descriptors and that DNA markers are necessary to separate morphologically related apricot landraces. The observed morphological and genetic differences suggest a loss of diversity influenced by maintenance breeding of specific pomological traits (e.g., skin colour and size). Finally, our study provided evidence to recommend complementary strategies to avoid the loss of diversity in apricot. Actions should pivot on both the promotion of easily identified premium products and more inclusive biodiversity-centred on-farm strategies.

Essential oils in Czech hop varieties

Czech hop varieties were evaluated as part of maintenance breeding. The evaluation was performed in a single location between 2011 and 2020. The average weight of hop essential oils (HEOs) is 0.43 to 2.28% w/w. The Saaz, Saaz Brilliant, Mimosa, Saaz Shine and Saaz Comfort hop varieties have a low amount of HEOs. Their maximum content of these compounds amounts to 1.1% w/w. The average proportion of myrcene is between 23.42 and 45.14% rel. Only the Agnus, Vital and Boomerang hop varieties have the maximum myrcene proportion above 50% rel. The average share of caryophyllene ranges between 6.19 and 13.15% rel. Saaz Late has a broad range of caryophyllene percentage – from 5.39% rel. to 15.53% rel. The average percenatge of farnesene is between 0.14 and 16.91% rel. Only the Saaz Comfort and Saaz Shine hop varieties have the maximum farnesene share above 20% rel. The average humulene content has a very broad range between 2.23 and 35.79% rel. The Vital, Mimosa, Gaia and Saaz Comfort hop varieties are in a group with a low humulene percentage, which is clearly different from other hop varieties. The average share of selinenes ranges broadly from 0.97 to 33.56% rel. Mimosa differs from the before mentioned varieties with its proportion of selinenes between 23.08 and 43.75% rel. The aim was to characterize and compare Czech hop varieties in terms of content and composition of HEOs.

Evaluation of Czech hop varieties

Czech hop varieties are evaluated as part of maintenance breeding. Every year, this evaluation includes ten mother plants of each hop variety. Yield is determined in kilograms of fresh hops per plant. The t-test is used to determine significance. Results from the years 2014–2019 show that Gaia and Kazbek have the highest yield (3.17 kg/plant and 3.05 kg/plant, respectively). Their yield is higher than that of the Harmonie, Agnus, Bohemie, Premiant, Sládek, Boomerang and Saaz varieties. Saaz has the lowest hop yield, i.e. 1.85 kg/plant. Bor, Saaz Late, Saaz and Sládek show the lowest variability, which ranges between 20.56 and 20.58%. Gaia has the highest variability (34.33%). Gaia also has the highest alpha acid content (12.30%) with a probability of 95% to 99%. Vital and Boomerang have a higher alpha acid content than other Czech hop varieties (11.09% and 10.81%, respectively) with a probability of 99%. Saaz Late (3.42%) and Saaz (3.06%) have the lowest alpha acid content with a probability of 95% to 99%. The variability of alpha acid content is considerably lower than the hop yield variability. Rubín has the lowest year-on-year variability of all Czech varieties (4.81%). Vital and Gaia have a very low variability (5.63% and 5.72%, respectively). A higher variability of alpha acid content was found in Saaz Late, Premiant, Agnus, Saaz, Kazbek, Bor and Harmonie, ranging between 8.01% and 10.21%.

Genetic analysis of some morphological traits in synthetic $$\times $$ naturally polyploid cotton derivatives

Cotton has received attention of geneticists since more than a century. Gossypium hirsutum, the predominantly cultivated cotton species worldwide, has a narrow genetic base. It is important to broaden its genetic base through introgression of novel alleles from related species. Here, we report the development and characterization of a backcross population derived from the hybridization of a 'synthetic' (derived by crossing and chromosomal doubling of nonprogenitor Gossypium species) and natural tetraploid upland cotton. 'Synthetic' was observed to be male-sterile and thus, was used as the female parent. A total of 7434 flowers were pollinated to obtain 1868 BC1F1 seeds by direct and reciprocal crosses. Characterization of the experimental plant material was conducted in the field for several morphological traits such as pubescence on the stem, leaf, petiole and bract, presence/absence of petal spot, petal margin colouration and stamen filament colouration. Genetic analysis revealed that petal margin colouration phenotype was governed by a single dominant gene, whereas the petal spot and filament colouration phenotypes manifested segregation distortion. None of the BC1F1 plants was devoid of trichomes thus demonstrating that presence of trichomes is dominant over their absence. Modern upland cotton cultivars are usually devoid of petal spot, petal margin colouration and stamen filament colouration. These floral anthocyanin pigmentation characteristics, if fixed in the cotton germplasm, may serve as diagnostic features for the identification of cultivars during DUS testing as well as in the maintenance breeding programmes.

Tensile strength of the rachilla in spikelets of Polish Festulolium braunii cultivars

The aim of this study was to evaluate the tensile strength of the rachilla in spikelets of Polish cultivars of Festulolium braunii (K. Rich.) A. Camus during seed development and maturation. The investigations were carried out in 2009 - 2010 at the Plant Breeding, Szelejewo, Poland. The inflorescences were randomly harvested in June - July from plant collection in maintenance breeding of three Polish cultivars (Agula, Felopa, and Sulino). Using a specifically developed testing machine, tensile strength of the rachilla of individual spikelets were determined. Regardless of the F. braunii cultivar, the tensile strength of the rachilla decreased through consecutive growth stages. The highest tensile strength of the rachilla was observed during the phase of kernel watery ripe stage (BBCH 71) - it ranged from 510.1 mN in 'Agula' to 592.0 mN in 'Felopa'. At the fully ripe phase (BBCH 89), the value of this trait ranged from 19.2 mN in 'Agula' to 45.0 mN in 'Felopa'. It was also observed that in all tested cultivars of F. braunii, the spikelets located in the lower part of the spike were characterised by the highest tensile strength of the rachilla, whereas those in the upper part were characterised by the lowest values of this trait. This means that the caryopses in the spikelets located at the lower part of the inflorescence were less susceptible to shedding. Seed shedding the Polish F. braunii cultivars, especially 'Agula' and 'Sulino', may start as early dough and soft dough phases. By contrast, seed shedding 'Felopa' is moved to the later phases of seed maturation.

Spontaneous outcrossing in tomato depends on cultivar and environment and varies between individual flowers

AbstractKnowledge about the degree of spontaneous outcrossing of diverse genotypes is essential for breeding programmes, maintenance breeding, and seed production. For tomato (Lycopersicon esculentum Mill.), very limited scientific evidence for genotypic differences is available and evidence from Europe is scarce. To close this knowledge gap, six cultivars were investigated in three Central European locations as part of the Organic Outdoor Tomato Project. To determine outcrossing rates, the monogenetic “cut‐leaf” trait, which is dominant over the “potato‐leaf” trait, was used as morphological marker. The observed range of outcrossing was 0.0%–5.2%. Outcrossing was significantly influenced by cultivar and environment. The outcrossing rate of individual flowers varied within cultivars ranging from 0% to 37%. The potential of newly opened flowers to accept foreign pollen varied largely with the cultivar. Genotypic differences could partly be linked to flower morphology traits. The potential for recombination between tomato genotypes is generally very low but can be a source for new variation in on‐farm management.

In vitro conservation of taro (Colocasia esculenta Var. Globulifera) as influenced by mannitol

In vitro conservation of germplasm plays a vital role in maintenance breeding and also has many advantages over the conventional system. The experimental results for conservation of Colocasia sp. also proved this. In relation to explants and osmoticum, meristem and axillary bud could be conserved for 24 months while meristem-base died after 6 months. Mannitol as osmoticum @ 4% performed nicely to conserve Colocasia upto 24 months. Only meristem and axillary bud could be conserved for 24 months with the use of 4 % mannitol. But other level of mannitol remained culture alive for varying periods (6 to 12 months). After 24 months, the plant height was 6.5 cm for the meristem and 6.4 for axillary bud.Bangladesh J. Agril. Res. 41(1): 67-74, March 2016

In Vivo Haploid Induction in Maize: Comparison of Different Testing Regimes for Measuring Haploid Induction Rates

The doubled‐haploid (DH) technology, based on in vivo induction of haploid seeds by pollen from inducer genotypes, has become routine in maize (Zea mays L.) breeding. De novo and maintenance breeding of inducers requires measuring the haploid induction rate (HIR) of numerous plants. We compared five testing regimes in combination with three inducers to find the best method for estimating HIR by discrimination of haploid (H) and crossing (C) seeds or plants with low false discovery rates (FDRs) and false negative rates (FNRs) in two experiments. Three testing regimes were based on tester genotypes LGT, GLT, and UFT equipped with the liguleless (lg2), glossy (gl), and herbicide‐resistance (uf) gene, respectively. One testing regime used classification of H and C seeds in crosses with a high‐oil tester (HOT). Embryo coloration as a result of the R1‐nj marker gene was used as another testing regime. Flow cytometry analysis or phenotyping of adult plants served as gold standard classification (GSC). With HOT, H and C seeds were not clearly distinguishable because of considerable overlapping of their oil content (OC) distribution. Estimates of HIR from LGT and UFT generally agreed well with HIR from GSC and showed acceptable FDR and FNR. The HIR determined with GLT showed a high Matthew correlation with the GSC but lower estimates as a result of higher FNR. The HIR estimated with the R1‐nj marker deviated considerably from HIR of GSC and had high FDR and FNR. Thus, we recommend LGT for determining HIR, but testing regimes UFT and HOT should be revisited.

Malpighia emarginata DC. bagasse acetone extract: Phenolic compounds and their effecton Spodoptera frugiperda(J.E. Smith) (Lepidoptera: Noctuidae)

Annually, several tons of residues that are rich in phenolic compounds are produced during the processing of acerola (Malpighia emarginata DC.) juice. Adding value to these residues is of great interest, since they can be a viable solution in the search for natural substances with insecticidal action and low impact on the environment and humans. Taking into account the economic losses from the attacks by the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in different crops, the objective of this study was to evaluate the effect of the extract of acerola bagasse flour (ABF) against this insect and determine the phenolic compounds in this extract. Bagasse of acerola (BRS238 or Frutacor clon) generated after juice production, was frozen and lyophilized. To obtain the extract, 6 g ABF was mixed with 60 mL acetone:water solution (7:3 v/v), and the extract was lyophilized. Spodoptera frugiperda caterpillars, 48 h-old, obtained by the maintenance breeding, were transferred to glass tubes supplied with an artificial diet containing the ABF extract at 0, 250, 500, 1000, and 2000 mg L-1 diet. The following variables were evaluated: duration and survival of larval and pupal stages, pupal weight, sex ratio, adult longevity, oviposition period, number of egg masses, and total number of eggs. The ABF extract contained several phenolic compounds including gallic acid, epigallocatechin gallate, catechin, p-coumaric acid, salicylic acid, and quercetin. The extract was toxic to S. frugiperda, prolonging the pre-pupal stage and increasing the mortality of caterpillars.

Breeding for wheat quality to assure food security of a staple crop: the case study of Tajikistan

This study evaluated options and obstacles to strengthening food security through breeding a staple crop in a developing country, using the case of quality of bread wheat in Tajikistan as an example. Three wheat varieties and 19 breeding lines were collected from two field trial locations included in the Tajik wheat breeding programme. Grain protein composition as a measure of quality was determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Payne scores were calculated in order to predict quality. There was high variation between and high heterogeneity within several lines and varieties in relation to protein composition. Differences between the same varieties/lines at different locations were also observed. The number of grains analysed from each variety/line allowed prediction of quality, and the majority of materials analysed showed high Payne scores. Based on Payne scores and cluster analyses, a group of varieties/lines with high quality was identified as interesting for further breeding. This study demonstrated the importance of improving wheat maintenance breeding and early generation seed production and of developing suitable screening methods for quality to secure food supply in developing countries such as Tajikistan.

Zasiedlenie przez grzyby mikroskopowe nasion rzadkich i zagrożonych gatunków roślin uprawianych w hodowli zachowawczej w Żywym Banku Genów w Jagniątkowie

Zasiedlenie przez grzyby mikroskopowe nasion rzadkich i zagrożonych gatunków roślin uprawianych w hodowli zachowawczej w Żywym Banku Genów w Jagniątkowie

AN AFLP-MARKER STUDY OF THE VITIS VINIFERA L. CULTIVAR 'WHITE RIESLING' COMPRISING 86 CLONES TO INVESTIGATE THE STABILITY OF CLONES

The cultivar ?White Riesling? is like any other cultivar of Vitis vinifera L. commercially asexually propagated. Therefore, any clone is asexually derived from a single individual. Genetic changes can only occur through mutations. The aim of this study was to analyse the number of mutations among 86 different ?White Riesling? clones and to characterise the kinds of mutations observed. Single event mutations, which only appear once in one clone, stay for the dynamic grapevine genome. Mutations, which appear frequently in different clones, imply that the mutations could be loci-specific. To examine this subject 86 ?Riesling? clones were analysed with ten amplified fragments length polymorphism (AFLP) primer combina¬tions. Of the 305 marker bands analysed 135 bands were polymorphic. 38.5% of the polymorphic marker bands showed single event mutations and 17% were specific-loci mutations. This indicates that the grapevine genome is dynamic and not stable. Since genetic variability is important for plant breeders but clone stability necessary for grape growers and winemakers the knowledge of genome stability is essential and could be an indication of how to deal with dynamic clones during the breeding proce¬dures, like clonal selection, and maintenance breeding.

Manutenção e reprodução de Anomalocardia brasiliana em condições laboratoriais

This study examined the filtration and ingestion rates from the Veneridae Anomalocardia brasiliana (Gmelin, 1791) and evaluated the efficiency of reproduction in laboratory. Specimens were collected on Mangue Seco beach, Pernambuco, Brazil. To evaluate the filtration and ingestion rates, experiments were carried out separately: the presence of light (2000 Lux) and absence of light, with three different temperatures (23.5, 27 and 30 oC), and different salinities (20, 25, 30 and 35 g L-1). Spawning was tested by manipulating temperature with the addition of microalgae and gametes in induction treatment and without manipulating water variables by spontaneous spawning treatment. The most active filtration and ingestion for the species occurred in the absence of light, at temperature of 27 oC, and salinity of 30 g L-1. It was found that there is no significant difference between the spontaneous and induction of spawning, however the spontaneous spawning showed a more significant amount of eggs and larvae. These results may contribute to the technology of maintenance breeding under laboratory conditions and seed production of this species for use in culture.

Genetic Diversity Analysis in a Novel Set of Restorer Lines of Pearl Millet [Pennisetum glaucum(L.) R. Br] Using SSR Markers

Forty five novel fertility restorers in pearl millet having good combining ability consisting of those identified from African collection and Indian breeding material were used to dissect the genetic relatedness deploying SSR markers. The highest PIC value obtained was for PSMP 2081 (0.83), PSMP 2089 (0.81) and PSMP 2090 (0.81) with a range of 0 to 0.83 with an average PIC of 0.53. The discrimination rate of the markers used for diversity analysis ranged from 0.35 to 0.67 with an average of 0.56 indicating their ability to discern the genetic distances adequately. DARwin's tree constructed using the SSR marker data formed eight distinct clusters with accessions of similar pedigrees grouping together though not as a rule. This study indicates the importance of maintenance breeding by detecting heterozygosity among the genotypes and the ability of SSR markers in discerning the diversity