Comparison of early generation yield testing and a single. Transgressive segregation for yield and oil content producing lines with considerably higher values than the better parent was observed in bc 2 f. After the desired level of homozygosity was achieved, the lines could then be tested for desired characteristics. Description two parental lines are crossed to generate f1 progeny which are then selfed to produce f2 plants. Advancement of generations can be performed in greenhouses ulhoa et al. The main objectives in this method include generation advancement of the crosses, handling of whole array of variation created in the crosses, and use of offseason nurseries to advance the. Mass, f 2derivedfamily, and singleseeddescent ssd selection methods were compared in an interracial population ica pijao. Singleseed descent is a plant that is selffertilized and the resulting seeds are collected. Pdf rice breeding for high yield by advanced single seed. Imc is more genotype dependent currently and that limits its application in routine breeding. Transgressive segregation for yield and oil content producing lines with considerably higher values than the better parent was observed in bc 2 f 4 and bc 2 f 5.
Single seed descent method this is the classic procedure of having a single seed from each plant, bulking the individual seeds, and planting out the next. Single plant selections, one panicle per plant pedigree selection method were used f 2 population in the greenhouse same population but planted in cone pots single seed descent ssd method employed expected 3. Pedigree breeding is a method of genetic improvement of selfpollinated species. Pdf predicting transgressive segregants in early generation. Breeder seed was produced at dass grand forks facility in north dakota in summer of 20. Instead of bulking whole seed lot of selected plants, a single seed is selected randomly from each selected plant to. A breeding procedure which is used with segregating population of self pollinated species in which plants are advanced by selecting single seed per plant from f 2 generation onward is called single seed descent method. This study was conducted to compare the effectiveness between the pedigree selection ps and single seed descent ssd methods in two yardlong bean crosses. Development of uniform f1 hybrid varieties of korean radish.
After four generations, random ssd and bpderived lines from two hybrid populations were evaluated in the f4, f5, and f6 generations in field experiments at two locations. Several breeding methods are available to plant breeders for germplasm improvement, such as the pedigree method, bulk method, single seed descent, backcross method, and recurrent selection. Repeated selfing or singleseed descent is the fastest way to achieve homozygosity with a group or family. Although the single seed descent method was not significantly different from the pedigree and bulk methods on a mean basis, it did derive a number of superior individual lines and preserved substantial betweenline variability for all traits measured, except spikes per meter. Goulden 1941 proposed a similar system without calling it ssd and it resulted from the interest of plant breeders to rapidly inbreed populations before evaluating individual lines.
Comparative efficiency of pedigree, modified bulk and. Comparison of pedigree selection and single seed descent for oil. Higher number of transgressive lines was obtained for three traits, including plant height, days to 50% flowering and number of panicle. Research comparison of conventional, modifi ed single seed. Single seed descent method this is the classic procedure of having a single seed from each plant, bulking the individual seeds, and planting out the next generation. Comparison of random bulk population and singleseeddescent. Crop science abstract simulated comparisons of single. In one procedure, a single seed was taken from each f 2 plant to produce the f 3 generation, the process was repeated for the f 4.
Comparative efficiency of pedigree, modified bulk and single. Singleseed descent, singlepod, and bulk sampling methods. An acceleratedgeneration increase program for establishing nearhomozygous lines was evaluated by both single seed descent ssd and random bulkpopulation bp methods. Rice breeding for high yield by advanced single seed. Predicting transgressive segregants in early generation using single seed descent method derived micromacrosperma genepool of lentil lens culinaris medikus. Using rapid generation advance with single seed descent in. The single seed descent method, propos ed by goulden 1939 and later m odified by grafius 1965, as a modification of the bulk breeding schem e, appears to hav e the characteristics to overcome the. The initial population of this study was a bc 2 f 1 from a cross between a well adapted and a high oil cultivar. Rice breeding for high yield by advanced single seed descent. Pedigree refers to record of the ancestry of an individual selected plant.
Comparative efficiency of pedigree, modified bulk and single seed descent breeding methods of selection for developing highyielding lines in rice oryza sativa l. Single seed descent method ssd is a modification of bulk method. Two plant breeding methods generally used in breeding selfpollinated crops, the bulkpopulation bp and the singleseeddescent ssd methods, compared by computer simulation to determine which retained the most additive genetic variation after four generations of inbreeding. The aim of the ssd procedure is to make many homozygous lines in a short time at a low cost.
Only then is line selection performed, regardless of the pedigree. Modifi ed single seed descent is a single seed descent procedure that bulks two. Predicting transgressive segregants in early generation using single seed descent methodderived micromacrosperma genepool of lentil lens culinaris medikus. First proposed by goulden 1939 and later modified by brim 1966. Development of uniform f1 hybrid varieties of korean. Selection is postponed in the second procedure to a more homozygous, f 6 generation, which is obtained by single seed descent. Single seed descent ssd this method is modification of bulk method. He noted that a wheat breeding program could be divided into two stages. Rice breeding for high yield by advanced single seed descent method of selection. Nov 29, 2012 the single seed descent ssd method of inbreeding minimizes the amount of genetic sampling. Pedigree method and single seed descent method authorstream. This paper reports the development of an rga technology that integrates the germination of immature seeds with single seed descent method of breeding. Single seed descent ssd is a specialized form of inbreeding where one grows the f2 generation under a high density and. Comparison of mass, f2derived family, and singleseed.
P006t78r was tested in the united states and canada. Further selection was based on yield, resistance to. The single pod descent spd and bulk methods bm produce redundant inbred lines that are descended. Ps and single seed descent ssd methods in two yardlong bean crosses. The singlepod descent spd and bulk methods bm produce redundant inbred lines that are descended from either the same f2 or f3 plant. Single seed descent ssd procedure for single seed descent method. These way 34 successive generations can be grown within a year. This process is generally continued upto f 5 generation. By this time desired level of homozygosity is achieved. Malinee janwan, tanee sreewongchai and prapa sripichitt. The theoretical changes in the mean and variance of a segregating population under single seed descent, a method of rapid generation advancement in selfpollinating crops, are discussed. The efficiency of pedigree and single seed descent selections for. It speeds up the breeding cycle, increases the number of. Abstract the single seed descent ssd method of selection has been evaluated in safflower carthamus tinctorius l.
Goulden 1941 proposed a similar system without calling it ssd. Genetical consequences of single seed descent in the breeding of. Genetics congress although he did not use the term single seed descent. Ssd method is the modification of bulk method, which is popular in many crops because of its practicality and usefulness.
Use of the single seed descent method in breeding safflower. The theoretical changes in the mean and variance of a segregating population under single seed descent, a method of rapid generation. Efficiency of single seed descent and early selection in the. An acceleratedgeneration increase program for establishing nearhomozygous lines was evaluated by both singleseed descent ssd and random bulkpopulation bp methods. Pedigree selection was the most effective simulated selection method at high 75% and moderate 50% heritabilities. Instead of bulking whole seed lot of selected plants, a single seed is selected randomly from each selected plant to make bulk. Rice improvement for high yield is important to increase productivity of the crop. Variety p006t78r was developed from the modified single seed descent method and selected based on yield, maturity, phytophthora sojae resistance and roundup branded herbicides resistance. From each of the selected plants, f3 seeds are harvested, bulked and planted. Bp breeding methods and used to compare the relative. Graduate thesis or dissertation a comparison of three. Use of immature seed germination and single seed descent for. Description two parental lines are crossed to generate f1. The selected seed is bulked and is used to grow the next generation.
Transgressive segregation for yield and oil content producing lines with considerably higher values than the better parent was observed in bc 2 f 4 and bc 2 f 5 generations. Single seed descent method this is the classic procedure of having a single seed from each plant, bulking the individual seeds, and. Plant breeding of chili peppers capsicum, solanaceae a. Because of the overall efficiency achieved with the single seed. A method to separate the inbreeding and selecting generations in order to speed the process along. With plants grown from selfed populations, there is a better probability of finding selfprogeny of all desired traits within a plant. This is the classic procedure of having a single seed from each plant, bulking the individual seeds, and planting out the next generation. Introduction there are several main breeding methods to develop new varieties for selfpollinated crops. Ac tends to be the most commonly used method although imc potentially has higher throughput and is less labour intensive. Field and computer simulation studies were used to estimate breeding progress with pedigree selection, single seed descent ssd and combinations of early generation pedigree selection followed by ssd. Mar 29, 2016 single seed descent method this is the classic procedure of having a single seed from each plant, bulking the individual seeds, and planting out the next generation. In this method, only one seed is selected randomly from each plant in f 1 and subsequent generations.
The results showed that immature 35dayold seeds can be used successfully to turn over a. The line advanced through plant row testing in chile in the winter of 201112 and preliminary trials in canada and northern us states in the summer of 2012. Single seed descent method can be used for quantitative traits selection because elite lines can selected, wide range of trait variation and high transgressive segregation are produced. The f 5 lines were then produced from the seed of individual f 4 plants single seed descent method, ssd. In soybean, ssd was found to be more efficient than pedigree selection for yield improvement. The ssd single seed descent method, which does not need selection during the breeding process, is also utilized in the development of recombinant inbred lines rils.
Handling of segregating generations backcross method of reeding its requirements and b applications procedure for transfer of single dominant gene and procedure for transfer of single recessive gene 16. Gy, for some classconditional seed distribution gy, using projected gradient descent pgd experimental details can be found in appendix a. The single seed descent ssd method of selection has been evaluated in safflower carthamus tinctorius l. Pdf on jan 1, 20, malinee janwan and others published rice breeding for high yield by advanced single seed descent method of. Single seed descent ssd is a specialized form of inbreeding where one grows the f2 generation under a high density and restricted water and nutrient supply to provide single stemmed plants with few grain. A report of the association of official seed certifying. The results showed that immature 35dayold seeds can be used successfully to turn over a generation of pigeonpea with 100% seed germination. It is a method of inbreeding a segregating population that is quite conducive to environments that are not typical. Pdf single seed descent method in plant breeding mugisha. Research comparison of conventional, modifi ed single. The theoretical changes in the mean and variance of a segregating population under single seed descent, a method of rapid generation advancement in. In separate populations, selection was applied for. Speed breeding technology shortens the breeding cycle and accelerates crop research through rapid generation advancement. The efficiency of pedigree and single seed descent selections.
It is a method which can handle segregating generations, in which f 2 and subsequent generations are harvested in bulk to grow the next generation. Speed breeding can be carried out in numerous ways, one of which involves extending the duration of plants daily exposure to light, combined with early seed harvest, to cycle quickly from seed to seed, thereby. The single seed descent ssd method of inbreeding minimizes the amount of genetic sampling. Conventional breeding techniques in sorghum sciencedirect. Ssd is a system to rapidly develop pure lines followed by selection among those pure lines. Single seed descent ssd is a method that enables plant breeders to advance generations while maintaining genetic variability johnson and bernard 1962. The single pod descent spd and bulk methods bm produce redundant inbred lines that are descended from either the same f2 or f3 plant. Modifi ed single seed descent is a single seed descent procedure that bulks two or three seeds from each plant during harvest. Use of immature seed germination and single seed descent. After the desired level of homozygosity was achieved, the lines could then be. At the end of bulking period, individual plant selection and evaluation is carried out in the similar fashion as in the pedigree method. The f 2 derivedfamily method involved elimination of lowyielding f 2 derived families in replicated yield trials in f 4, f 5 and f 6. The single seed descent method, propos ed by goulden 1939 and later m odified by grafius 1965, as a modification of the bulk breeding schem. There are many selection methods, but no method is perfect for general use with all crop plants.
Rapid generation advance rga with single seed descent is an effective tool for rice breeders. Breeders must carefully consider which method will be the most effective for their purposes. Ideally, samples from gy should be diverse and statistically similar to 3. October 4, 2007 at north carolina state university department of crop science.
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