Resistance to cracking.<p>

Frazier, W. A.<p>

Large numbers of varieties and breeding lines were again scored (scale 1 to
10, with 10 free of cracking) for resistance to fruit cracking.  The readings
were made for over-all cracking--radial, as well as concentric.  The most
resistant lines, along with susceptible checks, are compared below.<p>
<pre>

                      Cracking                          Cracking
Variety               Index     Variety                 Index

OSC 251 WC            10.0  VBL 2924-4-A-1-A.Acc.3062   8.8
OSC 284 WC            10.0  Ill. 1252-103-57            7.3
OSC 417 WC            10.0  Utah 122                    7.0
Acc. 180,725 USDA     10.0  Queens                      6.6
OSC 373 WC             9.9  Big Early Hybrid            6.6
OSC 250 WC.            9.9  FM  Pearson  VF  11         6.5
T-121 WC x dwarf F2    9.8  Calif. H-1                  6.4
        (dwarf)
T-121 arf F2           9.7  Harris Hybrid Lot 1453      5.4
        (normal)
N.Y.                   9.4  Early Pak                   5.3
T-141 CR F2            9.4  Stokesdale                  5.2
OSC 421                9.2  Queens B.C. det.            4.7
N.Y. 55-542            9.2  US 357                      4.4
5741-9 (Pearson)       9.2  Burpee 57                   4.2
OSC 405 WC             9.2  Jung Sugar Lump             3.9
OSC 263                8.9  Stokesdale BC               3.8
Campbell 54            8.8  100-5 FM                    2.6
</pre>

It is noted that the OSC (Wide Calyx) "WC" lines continue to exhibit high
resistance to cracking in this area.  This line of tomatoes, described in TGC
1:5 is considered to be a transgressive segregant out of the interspecific
cross, made in Hawaii, of Lycopersicon esculentum with L. hirsutum.  Material
sent to Young was studied by Butler, who used the term fleshy calyx and
designated it as the fl-allele.  It is suggested that the terminology and the
allele used by Butler be maintained, since it more accurately describes the
character.  The character, it is felt, shows intermediate segregation in F2.
Resistance to cracking in these lines may be partially associated with fl,
since the stem-end scar is unusually well protected.  Yet concentric cracks
are also uncommon, and perhaps the resistance to cracking could also be
considered transgressive in nature, and not entirely associated with fl.<p>

We feel that the u and d genes are also associated with resistance to
cracking.  We are slowly, through complex crosses, attempting to combine genes
for resistance to cracking in tomato.  There are undoubtedly genes (recessive
in nature) other than those mentioned here involved in resistance to cracking
(Young TGC 8:38), and it is believed highly worthwhile for tomato breeders to
take advantage of all of these genes in breeding for resistance to cracking.<p>
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