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Photosynthetic characteristics in wild, cultivated species and interspecific inbred lines of safflower

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Abstract

Safflower (Carthamus tinctorius L.), a multipurpose oilseed crop is the only cultivated species in the Carthamus genus. Carthamus spp. have been explored for resistance to biotic and abiotic stresses but not for physiological efficiency. Photosynthetic traits of ten wild and ten cultivated species and six interspecific inbred lines were studied to understand the expression of the photosynthetic traits among them, and for trait introgression from wild species in interspecific derivatives. Relations among some physiological traits in interspecific inbred lines differed from those observed in wild and cultivated species. The high photosynthesis (Pn), low transpiration (E) and high intrinsic water use efficiency (iWUE) could be introgressed from the wild species, C. lanatus and C. turkesthanicus into safflower cultivars. Inheritance of photosynthetic traits from wild to cultivated species indicated that wild species are exploitable for safflower improvement. This study suggests the utilization of wild species for their high Pn, low E and iWUE characteristics for developing abiotic stress-tolerant safflower cultivars.

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An interspecific cross was made between Carthamaus oxyacantha and the cultivated species C. tinctorius to develop a cytoplasmic-genic male sterility (CMS) system in safflower. C. oxyacantha was the donor of sterile cytoplasm. The 3: 1 segregation pattern observed in BC1F2 suggested single gene control with dominance of male-fertility over male-sterility. The information obtained from crossing male sterile X male fertile plants in BC1F3 and BC1F4 generations showed statistically significant single gene (1: 1) segregation for male sterility vs. male fertility. The results demonstrated that C. tinctorius possesses a nuclear fertility restorer gene and that a single dominant allele restored fertility (Rf) in progeny carrying CMS cytoplasm of C. oxyacantha. Male sterility occurred with the homozygous recessive condition (rfrf) in a sterile C. oxyacantha cytoplasm background and not in the normal cytoplasm of C. tinctorius. The genetic background of different restorer lines of C. tinctorius having normal cytoplasm did not effect fertility restoration. The absence of male sterile plants in C. tinctorius populations ruled out the possibility of genetic male sterility. Normal meiosis in F1 and BC1F2 ruled out a cytogenetic basis for the occurrence of male sterility.
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Photosynthetic rate (P N), SPAD value, specific leaf area (SLA), flag leaf area (FLA), and nitrogen content (LN) of genus Oryza were investigated and their correlation was analyzed to assess some of the main photosynthetic traits among different species in the genus Oryza. The results revealed wide variation in these traits. The species O. rufipogon and O. australiensis exhibited maximum photosynthetic rate. Comparison of different types of genomes (diploid: 2n=2x=24; tetraploid: 2n=4x=48) and growth habit (shade- or sun-grown) showed the species of diploid (with genome symbol EE; 2n=2x=24) genomes, with perennial and sun-grown species, had high apparent photosynthesis compared to others. The species with BB/BBCC, shade-grown and the tetraploids showed high SPAD value, and the flag leaf in sun-grown species and diploids were thicker (low SLA) compared with others. However, no significant difference could be noticed among the different types of genomes. Higher leaf area was noticed among the species of CC/CCDD genome, perennial shade-grown species and tetraploids than in others. The variety IR 36 exhibited highest leaf nitrogen concentration. Correlation analysis showed a strong relationship between P N and leaf nitrogen concentration while no marked relationships were observed among other characteristics. It implies that the species with thick and small leaves with high nitrogen concentration and high photosynthesis evolved better than others. O. rufipogon, with the same genome as O. sativa, could be one of the wild rice resources for elite crop improvement.
Article
Safflower (Carthamus tinctorius L.) is an important oil seed crop with growing importance in many countries around the world. However, safflower fly (Acanthiophilus helianthi Rossi) is one of the main limiting factors to expand the production area of the crop in several countries. Since host plant-resistance is the most efficient method for pest management, we evaluated a germplasm of wild accessions (Carthamus oxyacanthus Bieb.) with mostly brown–black seed coat color along with some white-seeded cultivated safflower genotypes for resistance to safflower fly. The results showed that there was a significant difference between two species for safflower fly damage with all cultivated genotypes being susceptible. However, for the accessions of C. oxyacanthus, a wide range of resistance was observed. In a choice experiment and natural infestation, 35.3–78.9 percent of heads per plant were infested in genotypes of C. tinctorius while for the accessions of C. oxyacanthus this was much smaller and ranged from 1.6 to 13.6%. In addition, percentage of seed yield loss per infested plant was more drastic in cultivated safflower (29.0–72.8%) than the wild accessions (0.0–21.4%). In the no-choice experiment, fly population was dramatically decreased in the wild accessions due to larval mortality and possibility of antibiosis. There was a strong relationship between brown–black seed coat color and resistance to safflower fly indicating the possibility of using this trait in breeding programs of safflower to develop fly-resistant cultivars.
Article
The yield potential (Yp) of a grain crop is the seed mass per unit ground area obtained under optimum growing conditions without weeds, pests and diseases. It is determined by the product of the available light energy and by the genetically determined properties: efficiency of light capture (epsilon i), the efficiency of conversion of the intercepted light into biomass (epsilon c) and the proportion of biomass partitioned into grain (eta). Plant breeding brings eta7 and epsilon i close to their theoretical maxima, leaving epsilon c, primarily determined by photosynthesis, as the only remaining major prospect for improving Yp. Leaf photosynthetic rate, however, is poorly correlated with yield when different genotypes of a crop species are compared. This led to the viewpoint that improvement of leaf photosynthesis has little value for improving Yp. By contrast, the many recent experiments that compare the growth of a genotype in current and future projected elevated [CO2] environments show that increase in leaf photosynthesis is closely associated with similar increases in yield. Are there opportunities to achieve similar increases by genetic manipulation? Six potential routes of increasing epsilon c by improving photosynthetic efficiency were explored, ranging from altered canopy architecture to improved regeneration of the acceptor molecule for CO2. Collectively, these changes could improve epsilon c and, therefore, Y p by c. 50%. Because some changes could be achieved by transgenic technology, the time of the development of commercial cultivars could be considerably less than by conventional breeding and potentially, within 10-15 years.
Molecular differentiation of Fusarium wilt resistant wild and cultivated species of safflower
  • K Anjani
  • P Ramayya
  • M V Kumar
Anjani K, Ramayya P J and Kumar M V 2011. Molecular differentiation of Fusarium wilt resistant wild and cultivated species of safflower. International Symposium Genomics of Crops, Medicinal Plants and Microbes, 29-31 May 2011, KAU, Thiruvananthapuram.
Cryptic genomic exchange between cultivated safflower (Carthamus tinctorius L.) and wild species C. glaucus, M.Bieb subsp. anatolicus (Bioss). -Proc. of Second National Plant Breeding Congress. Indian Society of Plant Breeders
  • K Anjani
  • M Pallavi
Anjani K and Pallavi M 2006. Cryptic genomic exchange between cultivated safflower (Carthamus tinctorius L.) and wild species C. glaucus, M.Bieb subsp. anatolicus (Bioss). -Proc. of Second National Plant Breeding Congress. Indian Society of Plant Breeders; TNAU, Coimbatore, India. pp. 187-193.
Transmission and expression of resistance to Alternaria leaf spot in a cross between Carthamus palaestinus x C. tinctorius. In 'Extended Summary: National Seminar on Changing Global Vegetable Oils Scenario: Issues and Challenges Before India
  • K Anjani
  • M Pallavi
  • R D Prasad
Anjani K, Pallavi M and Prasad R D 2007. Transmission and expression of resistance to Alternaria leaf spot in a cross between Carthamus palaestinus x C. tinctorius. In 'Extended Summary: National Seminar on Changing Global Vegetable Oils Scenario: Issues and Challenges Before India; Hyderabad, India, pp. 56-57.
Safflower-Hybridization of crop plants
  • P Knowles
Knowles P F 1980. Safflower-Hybridization of crop plants. Fehr W Rand Hadley H H (Eds.), ASA-CSA, Madison, WI, pp. 535-547.
Extended summaries, National seminar on changing global vegetable oil scenario: issues and challenges before India
  • M Pallavi
  • R D Prasad
  • K Anjani
Pallavi M, Prasad R D and Anjani K 2007. Novel sources of resistance to Fusarium wilt in Carthamus species. In: Extended summaries, National seminar on changing global vegetable oil scenario: issues and challenges before India. 29-31 January 2007, Indian Society of Oilseeds Research, Hyderabad, India.
Sources of resistance to Alternaria leaf spot among Carthamus wild species
  • R D Prasad
  • K Anjani
Prasad R D and Anjani K 2008. Sources of resistance to Alternaria leaf spot among Carthamus wild species. In: Safflower: Unexploited potential and world adaptability, Knights S E and Potter T D (Eds). Proceedings of the 7th International Safflower Conference, Wagga New South Wales, Australia.
Correlation of stomatal conductance with photosynthetic capacity of six walnut cultivars from the national assortment
  • A Sergiu
  • C Emil
  • F Marin
Sergiu A, Emil C, Marin F C and Irina A 2014. Correlation of stomatal conductance with photosynthetic capacity of six walnut cultivars from the national assortment. South Western Journal of Horticulture Biology Environment, 5(1): 1-10.