harditrus
What I Do
Blog for hardy citrus enthusiasts
About
I’ve had a passion for plant hybridization since I was a child. For the past 20 years I am obsessed by the goal to develop edible citrus varieties that can be grown under the climate of Paris region at the latitude 48N, far from traditional "citrus belt". Here I want to share my progress toward this task as well as to describe the basic knowledge of citrus biology and selection.
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My Project
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AfrikaansAlbanianAmharicArabicArmenianAzerbaijaniBasqueBelarusianBengaliBosnianBulgarianCatalanCebuanoChichewaChinese (Simplified)Chinese (Traditional)CorsicanCroatianCzechDanishDutchEnglishEsperantoEstonianFilipinoFinnishFrenchFrisianGalicianGeorgianGermanGreekGujaratiHaitian CreoleHausaHawaiianHebrewHindiHmongHungarianIcelandicIgboIndonesianIrishItalianJapaneseJavaneseKannadaKazakhKhmerKoreanKurdishKyrgyzLaoLatinLatvianLithuanianLuxembourgishMacedonianMalagasyMalayMalayalamMalteseMaoriMarathiMongolianMyanmar (Burmese)NepaliNorwegianPashtoPersianPolishPortuguesePunjabiRomanianRussianSamoanScots GaelicSerbianSesothoShonaSindhiSinhalaSlovakSlovenianSomaliSpanishSundaneseSwahiliSwedishTajikTamilTeluguThaiTurkishUkrainianUrduUzbekVietnameseWelshXhosaYiddishYorubaZulu
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Hardy Citrus Hybrids
Climate and soil
I live 40 km South of Paris, very close to the Seine river. My garden is situated on the South slope of a hill with the soil that is not particularly deep on the substrate of marl with white clay
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Thirty year average lows are 9°C that corresponds to the middle of USDA zone 9.
On average every 20 years there happens a profound winter freeze with night temperatures lower that -16°C with soil frozen during ~2 weeks.
Snow coverage happens every second year but stays on average during less than 3 days.
Basic techniques
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Most of my hybrids resulted from a controlled pollination of seed parent 5star citrumelo by different hardy or semihardy citrus varieties.
Flowers are castrated at the bud stage and pollinated two days after flowers are open.
Seeds are extracted from ripe fruits in the autumn and germinated in barely moist sterilized perlite in zip locked plastic bags at 30°C day and night.
Germination starts in roughly 10 days and seedlings are transferred in 15 cm pots .
They are grown at 18 hours a day fluorescent lights at 6000 lumens at 25°C.
In a spring they are transplanted in open ground without any protection in order to achieve frost selection.
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First Results​
Some of my seedlings already started to flower with fruits that are described in a blog section.
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Among them are
Ichangstars (a cross of FiveStarCitrumeloXC.ichangensis,
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Staraji (FiveStarCitrumeloXKeraji,
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Kuckletrumelos (KucleXFiveStarCitrumelo
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Staruzu (FiveStarCitrumeloXYuzu)
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