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Fifteen plants horn 8 llnes over 84 hours revealed that damage in 6 lines (12 plants) was less
than one arbitrary unit while 2 lines (3 plants) showed intermediate reaction.
In rice Ling et ai. (1985) observed resistance to brown spot disease in two plants regenerated
from 25% Heirninfhosporiurn oryzoe toxin medium and one plant horn toxin free medium. The
resistance was observed to be a dominant mutation with the resistant R1 heterozygote
segregating for resistance and susceptibility.
In Medicago sativa (alfalfa), Hahan et al. (19840) selected lines with increased resistance
to both the culture filtrate and the pathogen Fusariurn oxysporiurn 1. sp. rnedicaginis.
Resistance was observed to be associated with increased chromosome number, but in a
second experiment with shorter callus perlod, resistant plants wifh undtered chrornorm
number were obtained. Arcioni et 01. (1987) observed reduced regeneration capability of
callus treated with culture filtrate d Fusarium oxysporiurn 1. sp. rnedicaginis.
Other reports of in vitro selection are: Fusariurn oxysporiom resistance in tomato (Shahin and
Spivey, 1986) where the progeny of the initial regenerants segregated in a ratio d 3 resisfant
to 1 susceptible. The subsequent generation confirmed that the Fusariurn resirtant plants were
either homozygous or heterozygous domlnant lor the gene confening resistance.
Cdi lines and regenerated plants were alto selected for increased concentration of amino
acids. Reisch et el. (1981) regenerated 91 plants from 124 diploid aklia (HG2) cell lines
resistant to growth lnhibfflon due to ethionine (an analog d memionine). High concenttrdlon
of rnethionine, cyrlelne, cyrldhionine and giutathionine were observed in some of Ihe
emlonine rodstant callus cultures. One cell line R32 hod a ca. tenfold lnc- in soluble
rnothionlne. 43% increase in total free amlno acids and AOX Increase in amino acids and