Interesting article here i ran into off University of connecticut hemp & cannabis program resources directory. A copy and paste of the abstract, a brief insert, then link.
Either way, something to think about. No need to shoot the messenger....
Abstract. Feminized hemp seed producers often use selfing to maintain a strain name;
however, selfing may lead to inferior plants for cannabidiol (CBD) production. Using
three different hemp strains as parents [Candida (CD-1), Dinamed CBD, and Abacus],
two outcrosses [Candida (CD-1) 3 Abacus and Dinamed CBD 3 Candida (CD-1)] and
one self-cross [Candida (CD-1) 3 Candida (CD-1)] were conducted to produce feminized
seed. Progeny from the self-cross were significantly smaller and had less yield than
outcrossed progeny. Selfed progeny were variegated and highly variable for total dry
weight and floral dry weight. Discriminant analysis of principal components (DAPC)
using amplified fragment length polymorphism (AFLP) separated the three progeny
populations and showed that outcrossed populations clustered closer to the maternal
parent, possibly the result of a maternal effect. Analysis of molecular variance (AMOVA)
indicated that most variation (74.5%) was within populations, because the progeny from
all three populations are half-siblings of each other. The selfed progeny population had
lower expected heterozygosity (He = 0.085) than each of the outcrossed progeny
populations (He ’’ 0.10). These results suggest that selfed progeny may demonstrate
inbreeding depression resulting from enhanced expression of homozygous recessive
traits. It may be beneficial for feminized seed producers to use outcrossing instead of
selfing to generate feminized seed for CBD production
Insert 1:
Small (2015) reported that selfing in can-
nabis induces inbreeding depression. Our
findings provide phenotypic and genotypic
data to support this observation. Selfing,
when maternal and pollen parents are the
same genotype, to produce feminized seed
can result in less vigorous plants and reduced
yield. In addition, selfed plants have in-
creased homozygosity and may display del-
eterious recessive traits such as variegation.
If we make the assumption that our Candida
(CD-1) parental genotype was not the result
of selfing by the seed producer, then our
observations of variegation as early as the S1
compared with the S3 in strawberry (Jones
and Singleton, 1940) suggests inbreeding
may occur more rapidly in hemp than other
crops. Based on our observations, crossing
two different strains to maintain or increase
heterozygosity could be a strategy to increase
yields, and plants may be more uniform. If
crossing within a strain is necessary for legal
or economic reasons, then growers should
consider using two different genotypes of the
strain to produce feminized seed and main-
tain strain name. Hemp breeders may want to
consider developing inbred parental lines to
generate F 1 feminized seed, which could
produce plants that exhibit improved crop
uniformity and hybrid vigor. A limitation of
this study was that only three strains and the
progeny of three crosses were evaluated.
More research is needed to evaluate a broader
number of commercially available hemp
strains and additional generations of selfing.
Full Article:
https://cannabis-cahnr.media.uconn....es/2894/2020/09/2020_HortSci_TriploidHemp.pdf
Either way, something to think about. No need to shoot the messenger....
Abstract. Feminized hemp seed producers often use selfing to maintain a strain name;
however, selfing may lead to inferior plants for cannabidiol (CBD) production. Using
three different hemp strains as parents [Candida (CD-1), Dinamed CBD, and Abacus],
two outcrosses [Candida (CD-1) 3 Abacus and Dinamed CBD 3 Candida (CD-1)] and
one self-cross [Candida (CD-1) 3 Candida (CD-1)] were conducted to produce feminized
seed. Progeny from the self-cross were significantly smaller and had less yield than
outcrossed progeny. Selfed progeny were variegated and highly variable for total dry
weight and floral dry weight. Discriminant analysis of principal components (DAPC)
using amplified fragment length polymorphism (AFLP) separated the three progeny
populations and showed that outcrossed populations clustered closer to the maternal
parent, possibly the result of a maternal effect. Analysis of molecular variance (AMOVA)
indicated that most variation (74.5%) was within populations, because the progeny from
all three populations are half-siblings of each other. The selfed progeny population had
lower expected heterozygosity (He = 0.085) than each of the outcrossed progeny
populations (He ’’ 0.10). These results suggest that selfed progeny may demonstrate
inbreeding depression resulting from enhanced expression of homozygous recessive
traits. It may be beneficial for feminized seed producers to use outcrossing instead of
selfing to generate feminized seed for CBD production
Insert 1:
Small (2015) reported that selfing in can-
nabis induces inbreeding depression. Our
findings provide phenotypic and genotypic
data to support this observation. Selfing,
when maternal and pollen parents are the
same genotype, to produce feminized seed
can result in less vigorous plants and reduced
yield. In addition, selfed plants have in-
creased homozygosity and may display del-
eterious recessive traits such as variegation.
If we make the assumption that our Candida
(CD-1) parental genotype was not the result
of selfing by the seed producer, then our
observations of variegation as early as the S1
compared with the S3 in strawberry (Jones
and Singleton, 1940) suggests inbreeding
may occur more rapidly in hemp than other
crops. Based on our observations, crossing
two different strains to maintain or increase
heterozygosity could be a strategy to increase
yields, and plants may be more uniform. If
crossing within a strain is necessary for legal
or economic reasons, then growers should
consider using two different genotypes of the
strain to produce feminized seed and main-
tain strain name. Hemp breeders may want to
consider developing inbred parental lines to
generate F 1 feminized seed, which could
produce plants that exhibit improved crop
uniformity and hybrid vigor. A limitation of
this study was that only three strains and the
progeny of three crosses were evaluated.
More research is needed to evaluate a broader
number of commercially available hemp
strains and additional generations of selfing.
Full Article:
https://cannabis-cahnr.media.uconn....es/2894/2020/09/2020_HortSci_TriploidHemp.pdf
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