Table 1.
Origin and fruit traits of the accessions utilized in the present experiment.
Fig 1.
Diagram of genetic bridge (GB) and embryo rescue (ER) planned approaches to overcome interspecific barriers between C. annuum and C. baccatum.
Vertical arrows indicate the hybrid obtained, H = Hybrid, Ca = C. annuum, Cb = C. baccatum, Cc = C. chinense, Cf = C. frutescens, BC1 = First backcross, TWH = Three way hybrid.
Table 2.
SSRs utilized to confirm the hybridity of individuals obtained after interspecific hybridization [37].
Fig 2.
Cross diagram showing the results of the different crosses performed within the genetic bridge approach starting with crosses between C. annuum and the bridge species.
(A) First cross table indicates the crossability degree of C. annuum with C. chinense or C. frutescens, (B) Second cross table indicates the crossability degree of hybrids obtained in A with C. baccatum. Numbers over the cells indicate percentage of fruit set over an average of 25 artificial pollinations. Green indicates non-viable crosses, where no fruits were obtained (0% of fruits set, not indicated as number); blue indicates fruit set but non-viable seeds; red indicates fertile hybrids with normal development; and grey indicates hybrid inviable plants.
Table 3.
Descriptive results of the genetic bridge (GB) strategy using the alternative of obtaining hybrids between C. annuum (Ca) and C. chinense (Cch) for being subsequently crossed with C. baccatum to obtain three-way hybrids.
Cross combinations that did not set fruit or set fruit but seeds did not germinate are not included in the table.
Fig 3.
C. chinense (♀) × C. annuum (♂) hybrids showing virus-like syndrome (VLS).
(A) at 50 days after sowing, (B) 100 days after sowing, and (C) 150 days after sowing. Stunted growth, filiform leaves and short internodes can be observed.
Fig 4.
Cross diagram showing the results of the different crosses performed within the genetic bridge approach starting with crosses between C. baccatum and the bridge species.
(A) First cross tables indicate the crossability degree of C. baccatum with C. chinense and C. frutescens, (B) Second cross tables indicate the crossability degree of the hybrids obtained with C. annuum. Numbers over the cells indicate percentage of fruit set over an average of 25 artificial pollinations. Green indicates non-viable crosses, where no fruits were obtained (0% of fruits set, not indicated as number); blue indicates fruit set but non-viable seeds; red indicates fertile hybrids with normal development; and grey indicates hybrid inviable plants.
Table 4.
Descriptive results of the genetic bridge (GB) strategy using the alternative of obtaining hybrids between C. baccatum (Cb) and C. chinense (Cch) for being subsequently crossed with C. annuum to obtain three-way hybrids.
Cross combinations that did not set fruit or set fruit but seeds did not germinate are not included in the table.
Fig 5.
C. frutescens (♀) × C. annuum (♂) hybrids showing dwarfism and poor root development at 100 days after germination.
Table 5.
Descriptive results of the bridge cross technique using C. frutescens as genetic bridge between C. annuum and C. baccatum.
Those F1 combinations which did not set fruit, or set fruit but seeds did not germinate, are not included in the table.
Fig 6.
Comparison between normal and aborted seeds from crosses between C. annuum and C. baccatum.
(A) aborted seeds from interspecific cross between Bierzo (♀) × Aji Rojo (♂), and (B) normal seeds from self-pollinated C. annuum cv. Bierzo.
Fig 7.
Isolated embryos from interspecific crosses between C. baccatum and C. annuum before abortion.
Different deformities, due to early hardening of endosperm, can be observed.
Table 6.
Descriptive results of the direct cross and embryo rescue technique to obtain hybrids between C. annuum and C. baccatum.
F1 combinations that did not set fruit are not included in the table.
Table 7.
Descriptive results of the backcross and embryo rescue technique to obtain hybrids between C. annuum (Ca) and C. baccatum (Cb).
BC1 combinations that did not set fruit are not included in the table.
Fig 8.
Recommended diagram for wide hybridization between different species for introgression breeding of C. baccatum to C. annuum based on the results of this work.
Vertical arrows indicate the hybrid obtained, H = Hybrid, Ca = C. annuum, Cb = C. baccatum, Cc = C. chinense, BC1 = First Backcross, TWH = Three way hybrid.