Paper · 2026 · BMC Plant Biology

Dissecting heterosis and combining ability for yield and TYLCV resistance in tomato under field conditions

Mahnaz Hatamifard; Mahmoud Lotfi; Hossein Ramshini

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Open access · cc-by-nc-nd

Abstract

Tomato (Solanum lycopersicum L.) is one of the most important horticultural crops worldwide, with yield and fruit quality strongly constrained by biotic stresses, particularly tomato yellow leaf curl virus (TYLCV). Hybrid breeding through the exploitation of heterosis is a highly effective approach for improving yield, fruit quality, and TYLCV resistance. To investigate the genetic basis of heterosis and trait inheritance, 17 determinate female and 7 semi-determinate male inbred lines were crossed in a North Carolina Design II (NCII) scheme, generating 119 F₁ hybrids evaluated alongside their parents and control cultivars. To ensure uniform and consistent TYLCV infection pressure, the highly susceptible cultivar ‘Matin’ was interplanted throughout the field as a spreader genotype. Heterosis analysis revealed substantial positive better-parent heterosis (BPH) for yield-related traits, particularly single-plant yield and fruit number per plant, whereas negative heterosis was favorable for traits such as sunscald incidence, fruit acidity, and TYLCV severity. Genetic variance partitioning indicated that reproductive traits such as number of inflorescences on the main stem (NIMS), number of flowers per inflorescence (NFI), and number of fruits per inflorescence (NFPI) were predominantly governed by additive effects, suggesting that parental selection can efficiently improve these traits. In contrast, TYLCV resistance was strongly influenced by non-additive variance, highlighting the critical role of specific combining ability and hybrid interactions. Several hybrids combined high yield with complete resistance to TYLCV, underscoring the potential for simultaneous improvement of productivity and resilience. This study not only clarifies the genetic basis of heterosis in tomato but also identifies elite parental lines and superior hybrids that can serve as valuable resources for breeding programs aimed at developing resilient, high-yielding cultivars under biotic and climatic stress conditions.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by-nc-nd. Read at the source ↗

The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.

Claims 6

Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Substantial positive better-parent heterosis was found for yield-related traits in tomato hybrids, particularly single-plant yield and fruit number per plant.

Outcome
better-parent heterosis (BPH) for yield-related traitse0
Direction
positivee0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Solanum lycopersicum
Solanum lycopersicum · TaxonKod B · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“Heterosis analysis revealed substantial positive better-parent heterosis (BPH) for yield-related traits, particularly single-plant yield and fruit number per plant”

✓ located verbatim in the source · abstract, characters 792–955 · show in text ↑
t0

“tomato”

✓ located verbatim in the source · title, characters 77–83 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Negative heterosis was favorable for sunscald incidence, fruit acidity and TYLCV severity in tomato hybrids.

Interactor
TYLCVTomato yellow leaf curl viruse0pathogen
Outcome
sunscald incidence, fruit acidity, and TYLCV severitye0
Direction
negativee0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Solanum lycopersicum
Solanum lycopersicum · TaxonKod B · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“negative heterosis was favorable for traits such as sunscald incidence, fruit acidity, and TYLCV severity”

✓ located verbatim in the source · abstract, characters 965–1070 · show in text ↑
t0

“tomato”

✓ located verbatim in the source · title, characters 77–83 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Number of inflorescences on the main stem, flowers per inflorescence and fruits per inflorescence were predominantly governed by additive effects.

Outcome
reproductive traits such as number of inflorescences on the main stem (NIMS), number of flowers per inflorescence (NFI), and number of fruits per inflorescence (NFPI)e0
Qualifier
predominantly governed by additive effectse0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Solanum lycopersicum
Solanum lycopersicum · TaxonKod B · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“reproductive traits such as number of inflorescences on the main stem (NIMS), number of flowers per inflorescence (NFI), and number of fruits per inflorescence (NFPI) were predominantly governed by additive effects”

✓ located verbatim in the source · abstract, characters 1117–1331 · show in text ↑
t0

“tomato”

✓ located verbatim in the source · title, characters 77–83 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

TYLCV resistance in tomato was strongly influenced by non-additive variance, indicating a critical role of specific combining ability and hybrid interactions.

Interactor
TYLCVTomato yellow leaf curl viruse0pathogen
Outcome
TYLCV resistancee0
Qualifier
strongly influenced by non-additive variancee0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Solanum lycopersicum
Solanum lycopersicum · TaxonKod B · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“TYLCV resistance was strongly influenced by non-additive variance”

✓ located verbatim in the source · abstract, characters 1419–1484 · show in text ↑
t0

“tomato”

✓ located verbatim in the source · title, characters 77–83 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Several tomato hybrids combined high yield with complete resistance to TYLCV.

Interactor
TYLCVTomato yellow leaf curl viruse0pathogen
Outcome
high yield with complete resistance to TYLCVe0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Solanum lycopersicum
Solanum lycopersicum · TaxonKod B · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“Several hybrids combined high yield with complete resistance to TYLCV”

✓ located verbatim in the source · abstract, characters 1572–1641 · show in text ↑
t0

“tomato”

✓ located verbatim in the source · title, characters 77–83 · show in text ↑
Recommendationauthor interpretationoriginal resultpositivebasis n/a

Claim · model-written summary

The authors suggest that parental selection can efficiently improve the additively governed reproductive traits.

Outcome
efficiently improve these traitse0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Solanum lycopersicum
Solanum lycopersicum · TaxonKod B · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“parental selection can efficiently improve these traits”

✓ located verbatim in the source · abstract, characters 1349–1404 · show in text ↑
t0

“tomato”

✓ located verbatim in the source · title, characters 77–83 · show in text ↑