. 2020 Mar 19;11:195. doi: 10.3389/fpls.2020.00195

Table 3.

Potential applications of SI research in crop breeding and production.

Crop type	SI system^a	SI/SC^b	Potential applications of SI research	Refs.
Cereals crops
Wheat (Triticum aestivum)	GSI (S- and Z-loci)^a	SC	Introgression of SI from close relatives for developing hybrid seeds	Whitford et al. (2013)
Oilseed crops
Oilseed rape—canola (Brassica napus)	SSI	SC	Identification of new targets for inducing SC and methods to propagate SI lines for hybrid breeding	Yang et al. (2018)
Yellow mustard (Sinapis alba)	SSI	SI	Development of SI and SC inbred lines to produce high yielding synthetic varieties	Zeng and Cheng (2014)
Vegetable crops
Tomato (Solanum lycopersicum)	S-RNase based GSI Non-self recognition	SC	Introgression of crop wild relative traits into elite cultivars by overcoming IRBs depending on SI Development of ILs for genetic analysis	Tovar-Mendez et al. (2017)
Cabbage, broccoli, etc. (Brassica oleracea)	SSI	SI	Identification of new target genes conferring SC Development of SC lines for hybrid breeding	Xiao et al. (2019)
Tuber and root crops
Potato (Solanum tuberosum)	S-RNase based GSI Non-self recognition	SI/SC	Development of new CRISPR-KO SC diploid lines for efficient inbred/F1 hybrid strategies	Ye et al. (2018); Enciso-Rodriguez et al. (2019)
Radish (Raphanus sativus)	SSI	SI	S-genotyping for selecting weak SI plants as male and maintainer lines for hybrid breeding	Wang et al. (2019)
Fruit crops
Cherry, almond, apricot, and plum (Prunus spp.)	S-RNase based GSI Self recognition	SI/SC	Identification of new SC sources Development of new interspecific hybrids on the basis of possible relation between SI and IRBs	Muñoz-Sanz et al. (2017b); Morimoto et al. (2019)
Apple, pear, and loquat (Rosaceae subf. Maloideae)	S-RNase based GSI Non-self recognition	SI/SC	S-genotyping for identifying new pollenizers Development of new SC cultivars	Claessen et al. (2019); Sheick et al. (2018)
Orange, mandarin, lemon (Citrus spp.)	Unknown (GSI)^a	SC	Introgression of SI to reinforce seedlessness in commercial cultivars	Li et al. (2015); Kakade et al. (2017)
Olive tree (Olea europaea)	Unknown (DSI)^a	SI	S-genotyping for selecting pollenizers Development of SC cultivars	Saumitou-Laprade et al. (2017)
Beverage crops
Robusta coffee (Coffea canephora)	S-RNase based GSI^a	SI	Overcoming SI to increase productivity and to facilitate breeding and crossing with C. arabica	Asquini et al. (2011)
Tea (Camellia sinensis)	Unknown (LSI)^a	SI	Overcoming SI to develop SC homozygous lines that facilitate classical breeding	Zhang et al. (2016)
Cocoa (Theobroma cacao)	Unknown (LSI)^a	SI	Prediction of SI/SC genotypes Selection/development of high-yield SC plants	Lanaud et al. (2017)

SI systems where genetic control is unknown and/or whereS-determinants have not yet been identified. SSI, Sporophytic SI; GSI, Gametophytic SI; DSI, sporophytic Diallelic SI; LSI, Late acting SI; LSI.

Predominant expressed phenotype.