Heterosis in Pigeonpea

Category: Education

Presentation Description

Heterosis in Pigeonpea


Presentation Transcript


Heterotic Parameters, their Estimation and Hybrid Seed Production in Pigeon pea GM




The pigeon pea ( Cajanus cajan ) is a perennial legume from the family Fabaceae. Since its domestication in South Asia is at least 3500 years ago, its seeds have become a common food grain in Asia, Africa, and Latin America. HYBRID PIGEON PEA


HYBRID PIGEON PEA India has the largest pigeon pea growing area (3.5 m ha) with an estimated annual production of 2.5 m tons. The major pigeon pea growing Indian states are Maharashtra, Karnataka, Andhra Pradesh, Uttar Pradesh, Bihar and Madhya Pradesh. Pigeon pea is cultivated in the rainy season in diverse cropping systems. The early maturing (120-140 d) types are grown as a pure crop, while the medium (160-180 d) and long (>200 d) duration varieties are cultivated as an intercrop with sorghum, pearl millet, cotton, groundnut etc.


HYBRID PIGEON PEA Pigeonpea is cultivated in more than 25 tropical and sub-tropical countries, either as a sole crop or intermixed with such cereals as sorghum (Sorchum bicolor), pearl millet (Pennisetium glaucum), or maize (Zea mays), or with legumes, e.g. peanut (Arachis hypogaea).


HYBRID PIGEON PEA Pigeon pea may be self-pollinated crop, but up to 40% cross -pollination can occur. Therefore, it comes under the category of Often Cross-pollinated crops. Pigeon pea plant types may be determinate to indeterminate. MODE OF POLLINATION


HYBRID PIGEON PEA The foreign pollen has an advantage over native pollen in affecting fertilization. It has been proven by pollinating the flower buds by foreign pollen. It was observed that the percentage of ‘self’ was negligible when flower buds were pollinated with foreign pollen without emasculation. Some of the reasons attributed to it are delayed germination and slow pollen tube growth of the native pollen and thus it favours outcrossing.


HYBRID PIGEON PEA Anthesis normally occurs between 8.00 a.m. and 5.00 p.m. and flowers may remain open for 6 to 48 h. Flowering period is influenced by weather conditions. Anthesis


HYBRID PIGEON PEA Emasculation and Pollination Flowers are generally emasculated in the evening and pollinated in the next morning. For emasculation, flowers that will open one or two days later are selected, and the rest of the flowers and the buds in a branch are removed. The stamens of the selected buds are removed with a pair of a fine forceps by gently pushing the keels apart. The emasculated floral branch is then bagged.


HYBRID PIGEON PEA Self pollination To ensure selfing the flowers need to be bagged. This is because insects may sometimes carry pollen to the stigma and bring about cross-pollination.




HYBRID PIGEON PEA “Heterosis” is defined quantitatively as an upward deviation of the mid-parent, based on the mean values of the two parents (Johnson and Hutchinson, 1993). Heterosis is manifested as improved performance for F1 hybrids generated by crossing two inbred parents. Heterosis may be positive or negative. Depending upon the breeding objectives, both positive and negative heterosis are useful for crop improvement. In general, positive heterosis is desired for yield and negative heterosis for maturity.




HYBRID PIGEON PEA Heterosis is expressed in three ways, depending on the criteria used to compare the performance of a hybrid. The three ways are: mid-parent, standard variety and better parent heterosis. However, from the plant breeders’ viewpoint, better parent (heterobeltiosis, Fanseco and Peterson, 1968) and/or standard variety (standard heterosis) are more effective. Pigeon pea is a partially cross pollinated crop and the plants express strong heterosis in their F1 hybrids.


Measurement / Estimation of Heterosis Heterosis is estimated in three different ways, viz. (I) over mid parent, (2) over better parent, and (3) over commercial cultivar/hybrid. Thus on the basis of estimation, heterosis is of three types as given below: Average heterosis: When the heterosis is estimated over the mid parent, i.e., mean value or average of the two parents, it is known as average heterosis, which is estimated as follows Average heterosis = [(F1- MP)/MP] X 100 Where, F1 is the mean value of F1 and MP is the mean value of two parents involved in the cross.


Heterobeltiosis: When the heterosis is estimated over the superior or better parent, it is referred to as heterobeltiosis. It is worked out as follows: Heterobeltiosis = [(F1- BP)/BP] X 100 Where, BP is the mean value (over replications) of the better parent of the particular cross.


Useful heterosis : The term useful heterosis was used by Meredith and Bridge (1972). It refers to the superiority of F1 over the standard commercial check variety. It is also called as economic heterosis . This type of heterosis is of direct practical value in plant breeding. It is estimated as follows: Useful heterosis = [(F1- CC)/CC] x 100 Where, CC is the mean value over replications of the local commercial cultivar.


Standard Heterosis: Sometimes, heterosis is worked out over the standard commercial hybrid. It is estimated in those crops where hybrids are already available for comparison. This type of heterosis is known as standard heterosis. This is also of direct practical importance in plant breeding. It is estimated as follows: Heterosis = [(F1- SH)/SH] x 100 Where, SH is the mean value over replications of the standard (local commercial) hybrid. Heterosis leads to increase in yield, reproductive ability, adaptability, disease and insect resistance, general vigour, quality etc. For most of the characters, the desirable heterosis is positive. But for some characters, for example, earliness, height in cereals, micronaire value in cotton and toxic substances like neurotoxin in Lathyrus sativus, negative heterosis is important.






HYBRID PIGEON PEA Why Hybrids in pigeon pea? • 25-30% higher yield than varieties • Greater drought tolerance • Greater disease resistance • Greater stability


HYBRID PIGEON PEA ICRISAT along with its partners, has developed a new hybrid breeding technology, which is expected to enhance the production in farmers’ fields by a margin of 30% or more . This is expected to break the yield barrier in pigeon pea. Yield Enhancement in Pigeon pea through Hybrid Technology Pigeon pea breeder and DG (ICRISAT) in the field of hybrid pigeon pea


HYBRID PIGEON PEA ACHIEVEMENTS OF THE TECHNOLOGY The research on hybrid pigeon pea technology began with the discovery of a genetic male-sterility (GMS) system, leading to the release of the world's first pigeon pea hybrid, ICPH 8, in 1991. ICPH 8 recorded 25-30% higher yield over the best available variety, in farmers’ fields.


HYBRID PIGEON PEA ACHIEVEMENTS OF THE TECHNOLOGY This was followed by the release of five more GMS-based hybrids with a similar yield advantage. These hybrids, however, never became popular due to seed production problems. To further improve the hybrid seed production technology, ICRISAT and partners developed the cytoplasmic nuclear male-sterility (CMS) systems using the cytoplasm of wild relatives of pigeon pea (Table 1). PROBLEM AND ITS SOLUTION


HYBRID PIGEON PEA Genetic diversification of parental lines Search for new cytoplasm donors Trait based parental line development Molecular characterization of parental lines Human resource development Sharing technology with public and private sector FOR HYBRID DEVELOPMENT IN PIGEON PEA


HYBRID PIGEON PEA A4 is the best CMS system Among the five CMS systems developed, the one with A4 cytoplasm derived from Cajanus cajanifolius (Fig.) is the best. ICPA 2039 (Fig.), is a stable A4 CMS line, with no pollen shedders and a high frequency of stable fertility restorers.


HYBRID PIGEON PEA A strong pigeon pea breeding program at ICRISAT is diversifying the genetic base of the male- steriles and fertility restorers with increased emphasis on disease and insect resistance, stability, and yield. At present ICRISAT has 31 A4 CMS lines with a large variation for important agronomic traits (Table). Seven of these A-lines also have a high level of resistance to wilt and sterility mosaic diseases. PERFORMANCE OF CMS AND RESTORER LINES OF PIGEON PEA


HYBRID PIGEON PEA So far 91 fertility restorers of A4 cytoplasm have been identified in different maturity groups (Table 3). Of these, 37 restorers are resistant to wilt and sterility mosaic diseases. Large-scale see production of A-lines is undertaken in isolation (300- 400 m distance) using a row ratio of 1 male (B-line) : 4 female (A-line). Seed on the male-sterile plants is produced by cross-pollination carried out by a variety of insects (Fig.4). About 800-1000 kg ha-1 seed of A-lines can be harvested under good management. For hybrid seed production also, a row ratio of 4 A-lines : 1 R-line is used. At ICRISAT we harvested > 1000 kg ha-1 of hybrid seed of ICPH 2671 (Fig.5). To maximize the yield of A-line and hybrid, the male : female row ratio could be modified for different environments. Honeybee mediated out crossing






HYBRID PIGEON PEA How CMS System was introduced? SOURCES………. ICRISAT scientists integrated cytoplasm of a wild relative, Cajanus sericeus , with the nucleus of cultivated pigeon pea.


HYBRID PIGEON PEA • So far, three stable CMS lines in different phenologies have been bred and more than a dozen are in the final stages of development. • Maintainers and fertility restorers of CMS have also been identified and their genetic base diversified to develop hybrids in early-, medium- and long-maturity durations.


HYBRID PIGEON PEA • CMS lines from C. cajanifolius and C. scarabaeoides, other wild relatives of pigeon pea, appear very promising for plant type and fertility restoration. • PARTENERS: Mahyco Research Foundation and JK Agri-Genetics, Indian Council of Agricultural Research (ICAR).




HYBRID PIGEON PEA Characters showing heterosis Character Heterosis Example/remarks Earliness Higher negative heterosis Hybrid ICPH 2671 Maturity Higher negative heterosis six hybrids ICPH 2671, ICPH 3461, ICPH 3762, ICPH 3763, ICPH 4022, and ICPH 4024 exhibited significant negative heterosis. Plant height Positive heterosis ICPH 2671 (11.35%), ICPH 3933 (23.94%), and ICPH 3759 (8.28%) Showed significant positive heterosis over mid parent. Number of primary branches Positive heterosis Hybrids ICPH 2671, ICPH 2751, and ICPH 3759 expressed positive heterosis Pod clusters Positive heterosis ICPH 2671 and ICPH 3933 showed significant positive heterosis over mid and better parents


HYBRID PIGEON PEA Characters showing heterosis Character Heterosis Example/remarks number of pods plant-1 Higher positive heterosis ranged from -38.40 to 113.46%, -21.88 to 120.47% and -24.44 to 149.19% over better, mid and standard parent, respectively Seed size. Higher positive heterosis Hybrids ICPH 3477 and ICPH 3758 had significant positive heterosis over better and mid parents Wide range of positive and negative heterosis was observed for seed yield, hybrid ICPH 2671 (148.94-208.44%) exhibited the high heterosis in seed yield followed by ICPH 2740 (49.89-121.45%), ICPH 3477 (48.54-119.45%), ICPH 3491 (50.99-134.17%), ICPH 4017 (55.82-184.90%), and ICPH 4022 (127.23-155.64%) at different levels of heterosis, respectively.


HYBRID PIGEON PEA There was no significant inbreeding depression for days to flower and maturity and plant height. In case of number of pod cluster plant-1, inbreeding depression ranged from -64.50% (ICPH 3494) to 68.44% (ICPH 4012). For number of pods plant-1 ICPH 2671, ICPH 2740, ICPH 3359, ICPH 3461, ICPH 3758, ICPH 3933, ICPH 4012, and ICPH 4017 exhibited high heterosis and inbreeding depression. Observations on Inbreeding Depression


HYBRID PIGEON PEA Seventeen out of 22 hybrids, demonstrated significant inbreeding depression for seeds pod-1. For 100-seed weight, significant inbreeding depression was found in ICPH 3359 (19.61%). For seed yield plant-1, 14 hybrids showed 44.69 to 73.28% inbreeding depression. These results indicated the predominance of non-additive gene action. For plot yield, 12 hybrids exhibited positive heterosis and inbreeding depression ranging from 7.64 to 52.33%. The results on inbreeding depression suggested that the genes affecting yield showed both additive and non-additive gene action.


HYBRID PIGEON PEA Mature anthers of male fertile plants Mature anthers of male sterile plants


In News……….




This study dealt with the use of 148 simple sequence repeat (SSR) markers , including 32 novel markers reported here for the first time, on 159 A (cytoplasmic male sterile), B (maintainer) and R (fertility restorer) lines. In total, 41 (27.7%) markers showed polymorphism with 2 to 6 (average 2.6) alleles and 0.01 to 0.81 (average 0.34) polymorphism information content (PIC) value. Of these polymorphic markers, 22 SSR markers showed polymorphism between A (ICPA 2039) and R (ICPR 2438) lines of the commercial hybrid (ICPH 2438) ; however, only 21 of these SSR markers showed the same profile between A (ICPA 2039) and B (ICPB 2039) lines. Finally, two SSR markers, CCB4 and CCttc006, were found most suitable for purity assessment of hybrid seeds of the ICPH 2438 hybrid. The utility of these two diagnostic SSR markers has been demonstrated by using seed lots of this hybrid from two sources, ICRISAT and Mahabeej. It is anticipated that molecular diversity information generated on parental lines of hybrids under development, and identification of the two most suitable markers for testing the purity of hybrid seeds of ICPH 2438, will facilitate the pigeonpea hybrid breeding programme


Hybridity of the F 1  plant was affirmed by analyzing the morphological attributes, such as seed coat color, leaf shape, brown striations in the petal, pod features, and intermediate branching type etc. Most of the pollen mother cells (PMC) in the F 1  hybrid have shown regular meiosis, but in some PMCs chromosome heteromorphism was observed for two pairs of bivalents during diakinesis, leading to precocious separation of bivalents (62.81 %) at metaphase-I, and bridge formation (7.44 %) and laggards (2.48 %) at anaphase-I. SDS-PAGE of two major seed protein fractions (albumin and globulin) detected five polypeptide bands (Mol wt. 40.7, 39.8, 32.4, 23.5 and 19.5 KDa) unique to  C. scarabaeoides , the male parent, in the F 1 hybrids that evidenced the hybridity of F 1  plants. Further, RAPD and ISSR marker analysis revealed the hybrid nature of the putative F 1  plant. These analyses showed the inheritance of 28 RAPD and 12 ISSR markers, unique to  C. scarabaeoides  - the pollen parent, to F 1  hybrids.




HYBRID PIGEON PEA INTERPRETATIONS AND PRACTICAL UTILITY Early flowering and maturity are desirable traits in hybrid pigeon pea to escape Drought and adaptation to the moisture-stress environments. Hence negative heterosis for Days to flower and maturity is desirable. Hybrid ICPH 2671 ranked first for higher negative Heterosis indicating exploitable hybrid vigour for maturity. Also six hybrids ICPH 2671, ICPH 3461, ICPH 3762, ICPH 3763, ICPH 4022 and ICPH 4024 exhibited significant and negative heterosis. It was observed that the crosses maturing early involved at least one early maturing parent.


HYBRID PIGEON PEA Heterosis for plant height ranged from -7.24 (ICPH 4020) to 7.22% (ICPH 3759) for heterobeltiosis, -3.95 (ICPH 4020) to 23.94% (ICPH 3933) for relative heterosis and -6.88 (ICPH 4020) to 8.91% (ICPH 3359), respectively. For the number of primary branches, the range of heterosis over better, mid and standard parent was from -31.84 (ICPH 3933) to 24.50% (ICPH 3759), -30.72% (ICPH 3497) to 27.06% (ICPH 3759) and -27.7 (ICPH 3933) to 22.16% (ICPH 3497). Hybrids ICPH 2671, ICPH 2751 and ICPH 3759 were the top ranking crosses in positive heterosis.


HYBRID PIGEON PEA Thirteen hybrids showed positive heterosis in pod clusters over mid-parent, better parent and standard check. The per se performance of heterosis over better, mid and standard parent was from -67.17 (ICPH 3494) to 150.61% (ICPH 3933), -58.82 (ICPH 3494) to 175.93% (ICPH 3933) and -10.59 (ICPH 3763) to 186.82% (ICPH 2740), respectively.


HYBRID PIGEON PEA Number of pods plant-1, a major yield component exhibited higher magnitude of heterosis as compared to other traits and the heterosis ranged from -38.40 to 113.46%, -21.88 to 120.47% and -24.44 to 149.19% over better, mid and standard parent, respectively. Five hybrids ICPH 2671, ICPH 2740, ICPH 3359, ICPH 3477 and ICPH 4017 exhibited higher positive heterosis on all the three bases of estimation viz., mid parent, better parent and standard parent, respectively.


HYBRID PIGEON PEA Significant negative heterosis in pod width over better and standard parent was found in ICPH 2671, ICPH 3477 and ICPH 3933. The range of heterosis was from -16.44 (ICPH 3933) to 3.22% (ICPH 3497) for heterobeltiosis, 91 -5.95 (ICPH 3933) to 5.44% (ICPH 3497) for relative heterosis, and -9.61 (ICPH 3461) to 11.16% (ICPH 3497) for standard heterosis. ICPH 3491 manifested significant negative heterosis in the length of pod over mid and better parent.


HYBRID PIGEON PEA The range of heterosis over better, mid and standard parents was from -12.45 (ICPH 3491) to 4.56% (ICPH 4024), -9.41 (ICPH 3491) to 6.75% (ICPH 4024) and -4.32 (ICPH 3933) to 11.97% (ICPH 2740), respectively. ICPH 3491 and ICPH 3933 showed negative heterosis over different level of heterosis.


HYBRID PIGEON PEA The number of seed pod-1 is also an important character, which contributes to the higher yield. ICPH 2671 recorded significant positive heterosis over better, mid and standard parents. The range of heterosis in the present finding was from -6.60 (ICPH 3494) to 16.51% (ICPH 2671), -4.19 (ICPH 3491) to 17.82% (ICPH 2671) and -3.61 (ICPH 3491) to 9.84% (ICPH 2671). Hybrid ICPH 2671 had significant positive heterosis over different levels indicating more hybrid vigour in F1 .


HYBRID PIGEON PEA The range of heterosis for 100 seed weight varied from -17.33 (ICPH 3933) to 18.75% (ICPH 3477) for heterobeltiosis, -3.12 (ICPH 3933) to 25.00% (ICPH 3497) for relative heterosis and -3.85 (ICPH 3461 and ICPH 4019) to 19.23% (ICPH 3933) for standard heterosis. The hybrids ICPH 3477 and ICPH 3758 had significant positive heterosis over better and mid parents. Based on the present investigation, wide range of positive and negative heterosis was observed in seed yield plant-1. The estimated range of heterosis over better, mid, and standard parents was from -53.76 (ICPH 4020) to 129.18 (ICPH 2671), -46.66 (ICPH 4013) to 168.03% (ICPH 168.33), and -5.96 (ICPH 3497) to 154.66% (ICPH 4017), respectively.


HYBRID PIGEON PEA In general, positive and high magnitude of heterosis for grain yield plant-1 was noticed and this may be due to the heterosis contributed by one or more yield contributing characters. The estimated heterosis for seed yield was from -37.72 (ICPH 3763) to 148.94% (ICPH 2671) in heterobletiosis, -11.49 (ICPH 2751) to 190.09% (ICPH 2671) in relative heterosis and -29.93 (ICPH 3763) to 208.44% (ICPH 2671) in standard heterosis . Hybrid ICPH 2671 exhibited high heterosis in seed yield followed by ICPH 2740, ICPH 3477, ICPH 3491, ICPH 4017 and ICPH 4022.



authorStream Live Help